Weigh out the ingredients
You'll need flour, baking powder, salt, butter, brown sugar, sugar, eggs, vanilla, and chocolate chips.
Make the brown butter
Make the brown butter by heating unsalted butter over medium heat until the milk solids separate and turn golden.
Whisk together the cooled brown butter & sugars, then mix in the eggs & vanilla, and fold in the dry ingredients. Lastly, fold in the chocolate chips.
Make the batter
Transfer the batter to an 8" cake pan, and smooth out the top. Sprinkle more chocolate chips on top, then bake!
Allow the cookie cake to cool completely in the pan before removing.
Decorate the cooled cookie cake with buttercream as desired.
Enjoy this gooey cookie cake with a big glass of milk!