Preheat oven to 350 degrees F. Line a 9-inch square baking dish with parchment paper. Set aside.
In a medium-sized saucepan, melt butter over medium heat. Remove from heat and add ½ cup of semi-sweet chocolate morsels with the sugar. Stir until combined and morsels are melted.
Add in eggs, one at a time, stirring after each addition.
Add in vanilla extract.
Add cocoa powder, flour, salt, and baking powder. Using big stroked, stir JUST until combined and no longer see dry ingredients.
Fold in the crushed Oreos. Pour batter into the prepared baking dish.
Sprinkle the top with the remaining Oreo cookies that have been cut into fourths, as well as the remaining ½ cup of semi-sweet morsels.
Bake for 38 minutes. Remove from oven and cool COMPLETELY before cutting.