Using a mixer, beat the melted butter (make sure it is cooled to room temperature), brown sugar, and sugar on high speed for 2 minutes.
1 cup Unsalted butter, 1 cup Brown sugar, 1/2 cup White granulated sugar
Add in the eggs, egg yolk, and vanilla. Mix until combined.
2 Large eggs, 1 Egg yolk, 1 tsp Pure vanilla extract
Sift the flour, cocoa powder, baking powder, baking soda, and salt into the wet ingredients. Add in the Oreo crumbs and mix on low speed until just combined. It will be a thick dough.
2 3/4 cups All-purpose flour, 3/4 cup Unsweetened cocoa powder, 1/2 tsp Baking powder, 1/2 tsp Baking soda, 1 tsp Salt, 2 cups Oreo crumbs
Preheat the oven to 350℉. Line two cookie sheets with parchment paper. Let the dough rest for 10 minutes.
Once preheated, use a large cookie scoop ( 2oz or 2 TBSP) and scoop the dough. Place 6 cookie dough balls per cookie sheet.
Bake one cookie sheet at a time. Bake for 11 minutes. Take a 1/4th measuring cup and press it into the cookie. Bake for another 2 minutes.
Press the measuring back on the cookie. Let it sit for 5 minutes before transferring to a cooling rack. Cool the cookie completely.