Preheat oven to 350 degrees. Use parchment paper or a silpat mat to line a baking sheet. Cream the butter and brown sugar in a stand mixer until light and fluffy (about 2-3 minutes). Scrape the sides of the bowl to make sure all ingredients are blended.
Add in the egg and vanilla and beat until combined.
Add in flour, cornstarch, baking powder, and salt. Mix until all combined. Hand stir in the mini chocolate chips.
Scoop out 1 TBSP dough for smaller cookies (or 1/4 cup dough for BIG cookies) and roll into balls. Roll dough balls in crushed Chips Ahoy cookies. Place dough balls on prepared pan (12 cookies to a pan if smaller cookies) and slightly flatten with your hand to about 3/4 – 1 inch thick.
Bake for 10-11 minutes. Cool cookies cookie sheet for 10 minutes before removing to cooling rack. NOTE: If you decide to make the bigger cookies, you’ll need to bake them for 11-13 minutes.
While cookies are cooling, make the frosting.
In stand mixer, cream butter for about 1 minute until smooth.
Add in the vanilla extract, powdered sugar and heavy cream and mix on high for about 3 minutes until smooth. If the frosting is too thick, add more heavy cream a teaspoon at a time to get the consistency you are looking for. If frosting is too thin, add more powdered sugar.
Frost each cookie with a spreading knife. Sprinkle with Chips Ahoy crumbs and mini chocolate chips. Top each cookie with 1/2 Mini Chips Ahoy cookie.
Enjoy. Store in the refrigerator in an air-tight container for up to 5 days.