01 -
In a medium saucepan, melt the butter over medium-high heat. Add the sugar and cocoa powder once the butter is melted. Whisk to combine and remove from heat. Add the salt, vanilla, and eggs, and continuously whisk until the eggs are incorporated. Add the flour and mix thoroughly. Set the batter aside.
02 -
Cream together the butter and sugars in a stand mixer. Add the egg and vanilla, ensuring to scrape down the sides of the mixing bowl. Add the flour, salt, baking soda, and baking powder, and mix on low speed until fully incorporated. Gently fold in the chocolate chips. Set the dough aside.
03 -
Preheat the oven to 175°C (350°F). Line the bottom of a 9x9-inch baking pan with foil or parchment paper and lightly spray with non-stick baking spray.
04 -
Press the prepared cookie dough into the bottom of the baking pan as the base. Layer Oreo cookies on top of the dough without overlapping. Evenly pour the brownie batter over the Oreo layer.
05 -
Bake in the preheated oven for 35-40 minutes. To test for doneness, insert a knife into the center; if it comes out clean, remove the brownies from the oven. If batter sticks to the knife, bake for an additional 5 minutes. Let cool for at least 2 hours before slicing and serving.