DAY 1: MAKE THE DOUGH & JAM

1. Make the Enriched Yeast Dough:

• Lightly grease a large mixing bowl and set aside.
• In a large liquid measuring cup, combine the room temperature eggs, warm milk, and honey; whisk briefly.
• In the bowl of a stand mixer fitted with the paddle attachment, add the all-purpose flour, instant yeast, and salt. Stir on low speed to combine.
• With the mixer still on low, pour in the egg-milk mixture and mix just until a sticky dough forms.
• Continue on low speed and add the room temperature butter, one piece at a time, waiting until each piece is mostly incorporated before adding the next. Once all butter has been added, increase the speed to medium and beat for 1 minute until the butter is fully incorporated. The dough will be very sticky.
• Using a spatula, scrape the sticky dough into the prepared greased bowl.

2. Fold and Rise the Dough (2-Hour Process):

• Cover the bowl with plastic wrap and let the dough rise for 30 minutes.
• Uncover the dough. Wet your fingers or a spatula slightly, slide it underneath one side of the dough, gently pull it up, and fold it back over itself. Turn the bowl 90 degrees and repeat. Continue this folding process 6-8 more times until all sides have been folded over.
• Re-cover the bowl and let it rise for another 30 minutes.
• Repeat this entire folding process 3 more times, for a total of 4 sets of folds over a 2-hour period.
• After the final fold, tightly cover the bowl with plastic wrap and refrigerate overnight, or for up to 72 hours. This cold fermentation develops fantastic flavor.

3. Make the Rhubarb Blackberry Jam:

• While the dough is rising (or at any point on Day 1), make the jam.
• Place the chopped rhubarb, blackberries, granulated sugar, pinch of salt, and the split vanilla bean into a medium saucepan.
• Simmer over medium-low heat, stirring often, for about 30-40 minutes. The fruit will break down and the jam will thicken. The jam is done when it clings thickly to a wooden spoon.
• Remove from the heat and allow it to cool completely to room temperature. Remove and discard the vanilla bean pod. (Taste your cooled jam – if it needs brightness, stir in a squeeze of lemon juice, about ½ teaspoon at a time).
• Refrigerate the jam until ready to use.

DAY 2: ASSEMBLE, BAKE, AND ICE THE BUNS

1. Make the Streusel and Icing:

• Streusel: In the bowl of a stand mixer (or by hand), combine the all-purpose flour, granulated sugar, brown sugar, almond flour (or oats), salt, and cinnamon on low speed. With the mixer still on low, add the room temperature butter, one tablespoon at a time. Mix until the butter is incorporated and the mixture is crumbly. Set aside.
• Icing: In a small bowl, mix the room temperature cream cheese, milk, pinch of salt, and vanilla extract until smooth. Add 1 cup of the sifted powdered sugar and mix again until smooth. If the icing is too thin, add more powdered sugar until it reaches your desired drizzly consistency. Set aside.

2. Assemble the Buns:

• Line a half sheet pan with parchment paper (or generously grease a 10-inch pan).
• Remove the cold dough from the refrigerator. On a lightly floured surface, gently fold the dough over itself 3-4 times to form a smooth ball. Let the dough rest for 15-20 minutes to relax the gluten.
• Roll the rested dough into a rectangle that is about ¼-inch thick.
• Brush the entire surface of the dough with the 2 tablespoons of melted butter.
• Spread a thin layer of the cooled Rhubarb Blackberry Jam over the buttered dough (start with ½ cup, adding a bit more if needed). Don’t use too much jam, as it can make rolling very messy.

3. Cut and Proof the Buns:

• Starting at one of the short ends, roll the dough up tightly into a log.
• Using a sharp serrated knife or unflavored dental floss, carefully cut the log into 12 equal pieces.
• Arrange the buns, cut-side up, in the prepared pan, leaving about 1 ½ to 2 inches of space between them.
• Loosely cover the pan with plastic wrap. Let the buns proof (rise) at room temperature for 1 ½ to 2 hours, until they have almost doubled in size and look puffy. (Alternatively, for an overnight rise, place the covered pan in the refrigerator right after arranging the buns. In the morning, take them out and let them sit on the counter for about 45-60 minutes to come to room temperature before baking).

4. Add Streusel and Bake:

• Towards the end of the final proof, adjust an oven rack to the middle position and heat the oven to 350°F (175°C).
• Generously cover the tops of the proofed buns with the prepared streusel, gently pressing some of it into the buns to help it adhere. (You may have some leftover streusel).
• Place the pan in the preheated oven. Bake for about 22 to 27 minutes. The buns are done when the tops are light golden brown and the centers are set and spring back when gently poked.

5. Cool and Ice:

• Transfer the pan to a wire rack and let the buns cool for 10-15 minutes before icing.
• Drizzle the prepared cream cheese icing generously over the warm buns.
• Serve the Rhubarb Blackberry Streusel Buns warm and enjoy the fruits of your labor!