DAY 1 - PREPARE DOUGH AND CRUMBLE:

Make Cookie Dough:

• In a large bowl, cream together softened butter, powdered sugar, and brown sugar until light and fluffy, about 3-4 minutes with an electric mixer.
• Add egg, vanilla extract, and almond extract (if using). Mix well until fully incorporated.
• Add sourdough starter and mix until completely combined.
• In a separate bowl, whisk together flour, baking powder, salt, and cream of tartar.
• Gradually add dry ingredients to wet ingredients, mixing until just combined. Do not overmix.
• Dump dough out onto plastic wrap, wrap well, and refrigerate for 8-24 hours.

Make Fermented Crumble (Hand Method):

• In a medium bowl, mix flour, brown sugar, salt, powdered sugar, cinnamon, nutmeg, ginger, and sourdough starter.
• Add cold cubed butter and cut in using a pastry cutter or your fingers until mixture resembles coarse crumbs.
• Add vanilla and mix gently to incorporate.
• Cover and refrigerate alongside the cookie dough for 8-24 hours.

Make Fermented Crumble (Food Processor Method - Preferred):

• Add flour, brown sugar, salt, powdered sugar, cinnamon, nutmeg, ginger, and sourdough starter to food processor.
• Pulse 3-4 times to combine dry ingredients.
• Add cold cubed butter and pulse 10-15 times in short bursts until mixture resembles coarse crumbs.
• Add vanilla and pulse 1-2 times just to incorporate.
• Pulse until all ingredients combine until you have a brown sugar type texture to your crumble. You can squeeze it together and it will stay formed. Go slowly - you don’t want it to turn into a dough ball.
• Cover and refrigerate alongside the cookie dough for 8-24 hours.

DAY 2 - MAKE FILLING, ASSEMBLE, AND BAKE:

Make Apple Pie Filling:

• In a medium saucepan, combine diced apples, brown sugar, lemon juice, vanilla extract, cinnamon, nutmeg, ginger, and salt.
• Add butter and cook over medium heat, stirring gently, for 5-8 minutes until apples begin to soften and release their juices.
• In a small bowl, whisk cornstarch with 2 tablespoons of water to create a smooth slurry.
• Add the cornstarch slurry to the apple mixture and stir gently to combine.
• Continue cooking for 3-5 more minutes until apples are tender but still hold their shape and mixture thickens significantly. The filling should coat the back of a spoon.
• Remove from heat and let cool completely, at least 45 minutes. For faster cooling, cover with plastic wrap and refrigerate until cold.

Prepare for Assembly:

• Preheat oven to 350°F (175°C).
• Prepare a nonstick muffin pan. If your pan isn’t nonstick, lightly grease with butter or cooking spray or use a muffin liner.
• Remove cookie dough and crumble from refrigerator. Let the dough sit at room temperature for 5-10 minutes if it’s very firm.

Assemble Cookie Cups:

• On a lightly floured surface, roll out the fermented cookie dough to approximately 3/8 inch thick.
• Using a 2.5-3 inch circle cutter or wide mouth mason jar, cut out circles from the dough.
• Gently place each cookie round into a muffin cup, pressing it up against the sides all the way to the top to form a cup shape. Make sure there are no gaps or thin spots.
• Add a rounded tablespoon of cooled apple pie filling to the center of each cookie cup.
• Gently push down the apple filling to create an even layer in the cookie cup.
• Top with about 1 tablespoon of the crumble topping, sprinkling it evenly over the apple filling.

Bake:

• Bake at 350°F for 18-22 minutes, until edges are golden brown and crumble is lightly browned on top.
• Leave cookie cups in the muffin pan for 10 minutes to set.
• After 10 minutes, carefully remove from pan using a butter knife or offset spatula to gently lift them out.
• Place on a wire rack to cool completely, at least 1 hour.

Make Microwave Caramel:

• Warm the heavy cream gently on the stovetop or in the microwave until hot but not boiling. Set aside and keep warm. Alternately heat in the microwave for 15-30 seconds.
• Have your room temperature butter, salt, and vanilla extract measured and ready.
• Add water to a large, clear microwave-safe bowl with high sides first.
• Slowly pour the sugar into the center of the water. Do NOT stir.
• Place bowl directly in the microwave on HIGH for 1 minute.
• Continue microwaving in 30-second intervals until you’re past the 2-minute mark, checking after each interval.
• Once past 2 minutes, switch to 15-second intervals and check carefully after each one.
• Stop immediately when the mixture turns honey-gold in color, approximately 2-3 minutes total microwave time.
• Using oven mitts, carefully remove the bowl from the microwave and place on a heat-safe surface.
• Let it rest for about 1 minute without touching it. The caramel will darken to amber-brown from the residual heat.
• Slowly whisk in the warm cream, about 1 tablespoon at a time. The mixture will bubble vigorously.
• Once cream is fully incorporated, add the butter and whisk until completely melted and smooth.
• Whisk in the salt and vanilla extract until smooth.
• Let cool for a few minutes to thicken to drizzling consistency.

Final Assembly:

• Make sure your cookie cups are completely cool to the touch.
• Using a spoon or piping bag, drizzle the caramel generously over each cookie cup.
• If the caramel has cooled too much and thickened, gently reheat it in the microwave in 10-second bursts until it reaches drizzling consistency.
• Allow the caramel to set for 10-15 minutes before serving.