Almond Rhubarb Picnic Bars (A Beautiful Spring Bake!)

Introduction & Inspiration

Get ready to celebrate spring and early summer with one of the most beautiful and delicious baked treats imaginable: these Almond Rhubarb Picnic Bars! This recipe is a true delight, layering a tender, buttery shortbread crust with a luscious, nutty almond frangipane filling, all crowned with a stunning mosaic of fresh, tart rhubarb. It’s a sophisticated take on a classic fruit bar, perfect for sharing. The name itself invites you to pack them up for an elegant outdoor gathering, but they’re equally perfect for an afternoon tea or a special dessert.

My inspiration for this recipe comes from a deep love for the classic pairing of tart fruit with rich almond frangipane, often found in fancy patisserie tarts. I wanted to capture that elegant flavor combination in a more sturdy, shareable bar format. The author’s accidental discovery of the beautiful ombré or chevron pattern you can create with the rhubarb is a charming bonus that makes these bars a true work of art!

These bars are a wonderful baking project that yields stunning results. While they look impressive, the steps are straightforward, and the flavor is simply out of this world. It is a perfect recipe for rhubarb season.

Nostalgic Appeal / Comfort Factor

Classic fruit and shortbread bars are pure nostalgic comfort, evoking memories of bake sales, family picnics, and comforting homemade treats. Rhubarb itself, with its signature tartness and ruby-pink hue, is a nostalgic harbinger of spring for many, reminiscent of garden harvests and cherished family pie and crumble recipes.

This recipe takes those comforting elements and elevates them with the rich, slightly sophisticated flavor of almond frangipane. Yet, the overall experience remains deeply comforting – the buttery crust, the warm, nutty filling, and the tender-tart fruit are a timeless combination. The “picnic bar” concept itself is wonderfully nostalgic, promising a delicious, portable treat for a happy occasion.

It’s a dessert that feels both elegantly special and comfortingly familiar. A perfect comfort food with a gourmet touch.

Homemade Focus

This Almond Rhubarb Picnic Bar recipe is a fantastic celebration of from-scratch baking, where each layer is crafted with care to build a beautiful and delicious final product. You’re starting by making a simple, buttery shortbread crust, made incredibly easy in a food processor. The rich and nutty almond frangipane filling is also prepared from scratch, grinding toasted almonds for the best possible flavor.

The true homemade artistry shines in the final assembly. After par-baking the crust and spreading the frangipane, you’ll thoughtfully arrange the fresh rhubarb pieces on top. The recipe even guides you on how to create a beautiful chevron or ombré pattern with the rhubarb slices, a special touch that makes these bars a visual masterpiece.

It’s about taking fresh, seasonal ingredients and transforming them through classic baking techniques into something truly special, from the base to the beautiful fruit topping. The homemade quality is evident in every bite.

Flavor Goal

The primary flavor goal is a sophisticated and harmonious balance of buttery shortbread, rich and nutty almond frangipane, and bright, tangy rhubarb. The shortbread crust should be tender, buttery, and lightly sweet with a hint of salt to ground the flavors.

The almond frangipane filling should be moist, rich, and bursting with authentic almond flavor from both the ground toasted almonds and the almond extract. The rhubarb, cooked on top, should become tender and juicy, its natural tartness providing the perfect, refreshing contrast to the rich, sweet filling below. The final sprinkle of sugar on the rhubarb should help it caramelize slightly.

The overall experience should be a complex and delightful interplay of textures (crumbly crust, soft frangipane, tender fruit) and flavors (buttery, nutty, sweet, and tart). A perfect balance between flavour and texture.

Ingredient Insights

For the Shortbread Crust:

• All-Purpose Flour, Granulated Sugar, Salt: The basic building blocks for a simple, sweet, and balanced shortbread.
• Unsalted Butter (Cold): Essential for a tender, flaky shortbread texture. The recipe notes that cold butter is fine for the food processor method, as it will break down into the perfect size.

For the Almond Frangipane Filling:

• Sliced Almonds (Toasted and Cooled): Toasting the almonds before grinding them is a crucial step for developing a deep, nutty flavor.
• All-Purpose Flour & Tapioca Starch: The recipe lists “flour” and the previous day’s similar recipe used tapioca; here I will assume the 1 tbsp is AP flour as listed. This small amount gives the frangipane a little structure.
• Granulated Sugar: Sweetens the rich filling.
• Unsalted Butter (Cold): Provides richness and a creamy texture to the frangipane.
• Large Egg: Binds the filling together and helps it set during baking.
• Almond Extract & Optional Brandy: Enhance the almond flavor. Almond extract is potent, so a little goes a long way. Brandy adds a lovely warmth and complexity.

For the Rhubarb Topping:

• Fresh Rhubarb: The star! About ½ pound. The recipe gives wonderful instructions on how to cut it on the diagonal to create a beautiful pattern.
• Granulated Sugar (1 teaspoon): Sprinkled on top to help draw out juices and balance the tartness.

To Finish:

• Powdered Sugar or Jam: Optional finishes. Powdered sugar is simple and elegant. A warm jam glaze (like apricot) would provide a beautiful, glossy finish.

Essential Equipment

• 8×8-inch Square Baking Pan: The specified size for this recipe.
• Parchment Paper: Essential for creating a “sling” to easily lift the cooled bars out of the pan for clean cutting.
• Food Processor: Highly recommended for making both the crust and the frangipane filling easily and quickly.
• Cooling Rack: For cooling the baked crust and the finished bars.
• Knife: A sharp knife for trimming rhubarb and a serrated knife (as suggested in the recipe) for slicing the finished bars cleanly.
• Measuring Cups & Spoons (and optionally a Digital Scale): For accurate measurements, especially for baking.

Ingredients

(Based on 1x column)

Crust:

• ▢ 1 cup (125 grams) all-purpose flour
• ▢ ¼ cup (50 grams) granulated sugar
• ▢ ¼ teaspoon fine sea salt
• ▢ ½ cup (4 ounces or 115 grams) unsalted butter, cold, cut into chunks

Almond Frangipane Filling:

• ▢ ¾ cup (75 grams) sliced almonds, ideally toasted and cooled
• ▢ 1 tablespoon (10 grams) all-purpose flour
• ▢ A few pinches of sea salt
• ▢ 6 tablespoons (75 grams) granulated sugar
• ▢ 5 tablespoons (70 grams) unsalted butter, cold, cut into chunks
• ▢ 1 large egg
• ▢ ½ teaspoon almond extract
• ▢ Optional: 2 teaspoons brandy or another flavoring

Rhubarb Topping & Finish:

• ▢ ½ pound fresh rhubarb
• ▢ 1 teaspoon (5 grams) granulated sugar
• ▢ Optional: Powdered sugar or ¼ cup apricot jam for finishing

Step-by-Step Instructions

1. Prepare Oven and Pan:

• Preheat your oven to 350°F (175°C).
• Create a parchment paper sling for your 8×8-inch square baking pan: Cut two 12-inch lengths of parchment paper. Trim each to fit the 8-inch width of the pan. Press one sheet into the bottom and up the sides of the pan. Place the second sheet perpendicular to the first, covering the other two sides. This will make it very easy to lift the entire block of bars out later.

2. Make the Shortbread Crust:

• Food Processor Method: In the bowl of a food processor, combine the 1 cup of all-purpose flour, ¼ cup granulated sugar, and ¼ teaspoon salt. Pulse briefly to combine. Add the chunks of cold butter to the bowl. Run the machine continuously for 30 seconds to 1 minute, until the mixture clumps together and forms a soft dough.
• (Alternative No-Food Processor Method): If you don’t have a food processor, ensure your butter is at room temperature. Beat the butter and sugar together until creamy. Mix in the flour and salt until just combined. Chill the soft dough for about 15 minutes to make it easier to handle.
• Transfer the dough to your prepared baking pan. Press it evenly and firmly across the bottom and about ¼-inch up the sides of the pan.
• Par-Bake the Crust: Bake for 15 minutes, until the crust is very pale golden. For speed, the recipe suggests transferring the hot pan to a cooling rack in your freezer for 10 to 15 minutes while you prepare the filling.

3. Make the Almond Frangipane Filling:

• In your food processor bowl (no need to clean it after making the crust), combine the ¾ cup of toasted sliced almonds, 6 tablespoons granulated sugar, 1 tablespoon all-purpose flour, and a few pinches of sea salt. Grind these together until the almonds are powdery.
• Add the chunks of cold butter to the machine. Run the machine until the butter is fully incorporated and no large bits are visible.
• Add the large egg and any optional flavorings (almond extract, brandy). Blend just until the filling is combined into a smooth paste.

4. Assemble the Layers:

• Remove the mostly cooled crust from the freezer. It’s okay if it’s still slightly warm.
• Spread the prepared almond frangipane filling evenly over the par-baked crust.

5. Arrange the Rhubarb Topping:

• Trim your fresh rhubarb stalks. The recipe suggests cutting them in half horizontally (like splitting a hamburger bun) to get flatter pieces.
• Keeping the top (pinker) and bottom (greener) pieces matched, cut the stalks on a diagonal into about 1 ¼-inch lengths. This creates “V” shaped pieces.
• Arrange the rhubarb pieces, color side up, over the frangipane filling. For the ombré chevron pattern described, start with the greener segments at one end and gradually work your way to the pinker segments at the other end. (Or, as the author notes, simply scatter the pieces all over!).
• Sprinkle the 1 teaspoon of granulated sugar evenly over the fruit.

6. Bake the Bars:

• Place the pan on the middle rack of the preheated 350°F oven.
• Bake for 45 to 55 minutes. The bars are done when the frangipane filling is golden on top and a toothpick inserted into the almond cream (avoiding rhubarb) comes out clean. The rhubarb pattern may shift slightly as the filling puffs up.

7. Cool and Finish:

• Let the bars cool completely in the pan on a wire rack. For the cleanest cuts, it is best to chill the bars thoroughly in the refrigerator or even briefly in the freezer.
• Once cooled/chilled, use the parchment paper sling to lift the entire block out of the pan onto a cutting board.
• To Finish (Optional): Lightly dust the bars with powdered sugar. Alternatively, for a glossier, bakery-style finish, gently warm about ¼ cup of jam (apricot is lovely) and brush it over the top of the cooled bars.
• Using a sharp serrated knife, gently slice into 16 2×2-inch squares.

8. Serve and Store:

• Serve the Almond Rhubarb Picnic Bars chilled or at room temperature.
• While they can be stored at room temperature for a day or so, they keep longer and, as the author notes, taste wonderful when stored in an airtight container in the refrigerator.

Troubleshooting

• Crust Too Crumbly or Too Hard: Dough was overworked, or too much/too little butter used. Using the food processor method as described helps create a consistent texture.
• Frangipane Filling Oily or Separated: This can happen if the filling is over-mixed, especially after the egg is added, or if the butter was too warm. Mix just until combined.
• Rhubarb Releasing Too Much Water: This is natural for rhubarb. The long baking time helps evaporate much of this moisture. Ensure rhubarb isn’t frozen and unthawed (use fresh for best results).
• Bars Falling Apart When Cut: They were not chilled enough! Chilling the entire block of bars until very cold is the key to getting clean, neat slices.
• Rhubarb Still Too Tart: Rhubarb varies in tartness. If you know yours is very tart, you could increase the sugar sprinkled on top slightly, or serve with a sweet accompaniment like ice cream.

Tips and Variations

• The Parchment Sling is Your Friend: Don’t skip this step! It makes removing the bars from the pan for perfect cutting incredibly easy.
• Toasted Almonds Make a Difference: Toasting the sliced almonds before grinding them for the frangipane deeply enhances their nutty flavor.
• Cutting When Cold: As the recipe strongly suggests, these bars slice most cleanly when they are very cold. A gentle sawing motion with a serrated knife helps keep the rhubarb topping perfectly in place.
• Fruit Variations: This frangipane base is delicious with other tart fruits. Try sliced plums, apricots, or even pitted sour cherries instead of rhubarb.
• Nut Variations: You can use ground pecans or walnuts instead of almonds in the frangipane for a different nutty flavor profile.
• Add Spices: A pinch of ground cardamom or ginger would be a lovely addition to the frangipane filling, complementing the rhubarb beautifully.
• Doubling the Recipe: As noted in the original recipe, you can double all ingredients and bake in a 9×13-inch pan. Baking time may need to be adjusted slightly longer.

Serving and Pairing Suggestions

• Serve Chilled or at Cool Room Temperature: The texture is best when cool and firm.
• Perfect for Picnics: As the name implies, these bars are sturdy enough to travel well (when chilled), making them perfect for picnics, potlucks, and outdoor gatherings.
• With Coffee or Tea: An elegant and buttery bar perfect for an afternoon treat.
• Dessert Platter: Cut into small squares, they make a beautiful addition to a dessert platter.

Nutritional Information

(Note: Estimated, per 2×2-inch square bar, assuming 16 bars. This is a rich, buttery dessert.)

• Calories: 180-250
• Fat: 12-18g
• Saturated Fat: 6-9g
• Cholesterol: 30-45mg
• Sodium: 80-120mg
• Total Carbohydrates: 18-25g
• Dietary Fiber: 1-2g
• Sugars: 10-15g
• Protein: 2-4g

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Recipe Summary and Q&A

Summary: These Almond Rhubarb Picnic Bars feature a buttery shortbread crust (made easily in a food processor) which is par-baked and cooled. A rich almond frangipane filling (ground toasted almonds, sugar, butter, egg, flavorings) is spread over the crust. Fresh rhubarb, cut on a diagonal, is arranged decoratively on top and sprinkled with sugar. The bars are baked until golden and set, then cooled completely. After thorough chilling for easy slicing, they can be finished with a dusting of powdered sugar or a warm jam glaze.

Q&A:

• Q: What is frangipane?
  • A: Frangipane is a classic pastry filling made from almonds (usually ground), butter, sugar, and eggs. It has a rich, nutty flavor and a soft, moist texture when baked, almost like a dense almond cake. It’s a traditional component in many French tarts and pastries.
• Q: Do I really have to make the fancy rhubarb pattern on top?
  • A: Not at all! As the recipe author delightfully notes, “you could just scatter pieces all over and it will all taste the same in the end.” The decorative pattern is a fun, artistic touch if you’re feeling creative, but simply scattering the chopped rhubarb over the frangipane will be just as delicious.
• Q: Can I use frozen rhubarb?
  • A: Fresh rhubarb is recommended for the best texture and for creating the decorative pattern. If you must use frozen rhubarb, it’s best to thaw it completely and drain off as much excess liquid as possible to prevent making the frangipane filling too watery. The texture of the baked rhubarb may also be softer.
• Q: Why is it so important to chill the bars before cutting?
  • A: Chilling solidifies the butter in both the crust and the frangipane filling. This makes the bars very firm, which allows you to get clean, neat slices without the layers squishing or the topping sliding around. It’s the secret to professional-looking bar cookies!