Preheat oven to 350 degrees F (177 degrees C). Line a 9x13 baking dish with parchment paper and set aside.

In a large mixing bowl, whisk melted butter, vegetable oil, both sugars, and vanilla together. Add eggs one at a time, whisking them in well before each addition.

Add in flour, cocoa, baking powder and salt and mix in with a rubber spatula or wooden spoon until flour is just incorporated.

Pour brownie batter into lined baking dish and bake for 35-40 minutes in oven. 35 for an intensely fudgy brownie, closer to 40 for more "set up" brownies as seen in the photos.

Pull brownies from oven and let cool for 30 minutes to an hour. The crust will be puffy until cooled, the brownie crust will harden and the insides will set once cooled.