Preheat oven to 350 degrees. Brush a 6 inch cast iron skillet with oil, set it aside.
Add butter to a medium saucepan and cook over medium heat until light brown/caramel in color. 5-10 minutes. Make sure to keep an eye on it so the butter does not burn. It also helps to use a light-colored saucepan for this.
Pour browned butter into a large bowl along with both sugars, cocoa powder, salt, instant coffee granules, and baking powder. Stir until combined and allow to rest for 5 minutes or until the mixture has cooled down.
Stir in the egg and vanilla and mix until batter has a nice sheen to it.
Fold in the flour and stir until combined. Add in the chocolate chips stir until combined. (Do not over mix).
Pour the batter into the prepared pan and bake for 13-15 minutes or until the top is set.
Allow to cool for 5 minutes then dig in and enjoy!