1. Prepare Jars and Start Shortcake Batter:

• Gather all your ingredients. Grease 6 half-pint heatproof jars well. Have their lids and bands ready.
• In a large mixing bowl, whisk together the 1 ½ cups all-purpose flour, ¼ cup granulated sugar, 1 teaspoon baking powder, ½ teaspoon salt, and ¼ teaspoon baking soda until well combined.
• Add the ⅓ cup of cold, cubed butter to the dry ingredients. Using a pastry cutter, two knives, or your fingertips, cut the butter into the flour mixture until it resembles coarse crumbs with some small pea-sized pieces of butter remaining.

2. Finish Shortcake Batter and Fill Jars:

• In a separate medium bowl, whisk together the room temperature large egg, ¾ cup sour cream, 3 tablespoons RumChata liqueur, and 1 teaspoon vanilla extract until smooth.
• Pour this wet mixture all at once into the dry ingredient/butter mixture.
• Stir with a fork or rubber spatula just until the dough is moistened and comes together. Be very careful not to overmix; a slightly shaggy dough is good.
• Spoon the prepared shortcake batter evenly among the 6 greased half-pint jars, filling each about half to two-thirds full (it will rise).
• Center the flat lids on the jars and screw on the bands until just “fingertip tight” – do not overtighten, as air needs to escape.

3. “Bake” Shortcakes in Slow Cooker Water Bath:

• Carefully place the filled and sealed jars upright into the insert of a 6- or 7-quart oval slow cooker.
• Add enough hot (but not boiling) water to the slow cooker to reach about halfway up the sides of the jars. This creates a water bath. The recipe suggests about 5 cups of water.
• Cover the slow cooker securely with its lid.
• Cook on the HIGH setting for 1 ½ to 2 hours. The shortcakes are done when they are puffed, set, and a toothpick inserted into the center of a shortcake comes out clean or with just a few moist crumbs.

4. Make the Pineapple Topping:

• While the shortcakes cook (or during the last hour), prepare the pineapple topping.
• Cut the fresh pineapple into ½-inch pieces. You’ll need 1 ½ cups.
• In a medium bowl, combine the 1 ½ cups of fresh pineapple pieces, 2 tablespoons of the granulated sugar (reserving 1 tbsp for the whipped cream), 1 to 2 tablespoons of RumChata liqueur, and 1 teaspoon of grated lime zest.
• Stir gently to combine. Cover the bowl and refrigerate for at least 1 hour to allow the pineapple to macerate and the flavors to meld.

5. Cool Shortcakes:

• Once the shortcakes are cooked, carefully remove the hot jars from the slow cooker (using tongs or oven mitts) and place them on wire racks to cool completely. The lids may seal as they cool; this is okay.

6. Whip Cream:

• Just before serving (or when shortcakes are cool), make the whipped cream.
• In a chilled medium bowl, beat the ½ cup of cold heavy whipping cream with an electric mixer (whisk attachment) until it begins to thicken.
• Gradually add the remaining 1 tablespoon of granulated sugar. Continue to beat until soft or medium peaks form. Be careful not to overwhip into butter.

7. Assemble and Serve:

• Once the shortcakes in the jars are completely cool (or still slightly warm if preferred), carefully open the jars.
• To serve, spoon a generous portion of the chilled Pineapple-RumChata topping (with its juices) over each shortcake in its jar.
• Top with a dollop of the freshly whipped cream.
• If desired, garnish with a thin slice of fresh lime.
• Serve immediately and enjoy these unique and delicious shortcakes!