1: Preheat oven to 350 degrees Fahrenheit.
2: In a bowl, whisk together the melted butter, oil, and sugars.
3: Once incorporated, add in the eggs and vanilla, whisk again until smooth and creamy.
4: Using either a metal sieve or a sifter attachment, sift together the flour, cocoa powder, and salt.
5: Add the dry mixture to the wet mixture and fold together. Be sure not to over mix.
6: Put the mixture into a baking dish lined with parchment paper.
7: Bake for a total of 30-35 minutes, checking after the first 15 minutes, then about every 5 minutes after that.
8: Let them cool completely before cutting.
