Cream the butter and sugars: In a large bowl or stand mixer fitted with the paddle attachment, beat 0.75 cup softened unsalted butter, 0.5 cup granulated sugar and 0.25 cup packed light brown sugar on medium speed until light and fluffy, about 2–3 minutes.

Add egg and flavoring: Beat in 1 large egg until incorporated, then add 1 teaspoon vanilla extract and mix until smooth.

Combine dry ingredients: In a separate bowl whisk together 1.75 cups all-purpose flour, 0.25 cup unsweetened cocoa powder, 0.5 teaspoon baking soda, 0.25 teaspoon salt, and 2 tablespoons strawberry powdered drink mix (or freeze-dried strawberry powder). Make sure the powdered strawberry is evenly distributed.

Mix dry into wet: With the mixer on low, gradually add the dry ingredients to the creamed butter mixture and mix until just combined, scraping the bowl as needed. Do not overmix.

Fold in mix-ins: Using a spatula, fold in 0.5 cup mini rainbow sprinkles and 1 cup roughly chopped mini chocolate sandwich cookies (mini Oreos) until distributed evenly through the dough. The dough will be slightly thick and pliable.

Portion dough: Using a cookie scoop or tablespoon, portion dough into 1.5 tablespoon (about 22–24 g) rounds — you should get approximately 24 cookies. Place dough balls about 2 inches apart on prepared baking sheets.

Bake: Bake in the preheated oven for 9–11 minutes. Cookies should be set at the edges but still slightly soft in the center; they will continue to firm while cooling.

Cool: Remove from oven and allow cookies to cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely before sandwiching with filling.

Filling (strawberry cream)

Beat filling base: In a medium bowl or using the stand mixer (paddle attachment), beat 0.5 cup softened unsalted butter and 0.25 cup softened cream cheese together until smooth and creamy, about 2 minutes.

Add powdered sugar and flavor: Gradually beat in 1.75 cups powdered sugar on low until incorporated. Add 1 teaspoon strawberry extract and 1 teaspoon strawberry powdered drink mix, plus a pinch of salt. If the filling is too thick, add up to 1 tablespoon milk, 1 teaspoon at a time, until you reach a pipeable/spreadable consistency.

Adjust sweetness and texture: Taste and adjust — add a little more powdered sugar to stiffen or a drop more extract for stronger strawberry flavor. Transfer filling to a piping bag or small bowl for assembly.

Assemble and finish

Match cookies: Pair cooled cookies by similar size so sandwiches sit evenly.

Pipe or spread filling: Pipe or spread about 1 to 1.5 tablespoons of strawberry cream onto the flat side of one cookie, then top with its matching cookie to create a sandwich. Press gently to spread filling to the edges.

Roll in sprinkles / press chopped Oreos (optional): If you want extra decoration, spread extra sprinkles (0.25 cup) or extra chopped mini Oreos (0.25 cup) on a shallow plate and roll the edges of each sandwich briefly to coat the filling edges. Press firmly but gently so the filling picks up the toppings.

Set: Place finished sandwiches on a wire rack and chill for 15–20 minutes to let the filling firm, which makes them easier to handle and slice (if desired).

Storage: Store cookies in an airtight container in the refrigerator for up to 5 days, or freeze for up to 1 month (freeze unfilled cookies flat; fill after thawing, or freeze assembled and separate layers with parchment). Bring to room temperature 10–15 minutes before serving for best flavor.