Preheat oven to 350°F. Grease half of a 12-cup muffin tin with non-stick cooking spray (this recipes makes 6 cups). 

In a large mixing bowl, whisk together melted butter, sugars, and vanilla until combined. Add flour, cornstarch, salt, baking powder, and baking soda. Use a wooden spoon or spatula to fold dry ingredients into wet until a soft dough forms. Fold in white chocolate chips and sprinkles. 

Scoop 2 ½-3 tbsp dough into each muffin cup and lightly press dough down so it sits evenly in the bottom (do not press up the sides yet). 

Bake for 13-14 min until edges are set. The center should still look soft and slightly underbaked. 

Remove from oven and immediately use the bottom of a ¼ cup measuring cup to gently press into the center of each cookie to form a cup shape. 

Cool cookie cups for 10 minutes before carefully removing. Cool completely before filling. 

Make the filling: in a medium mixing bowl, use a handheld mixer to cream together cream cheese, butter, and vanilla until combined. Slowly mix in powdered sugar until a creamy frosting forms. 

Fill each cooled cookie cup with dunkaroo filling. Top with a teddy graham or cookie and rainbow sprinkles