Preheat oven to 350℉ (180℃)
Place cocoa powder in a large mixing bowl.
¼ Cup Cocoa Powder, Unsweetened
Bring coffee (or water) to a vigorous boil and pour over cocoa powder. Whisk until combined.
½ Cup Brewed Coffee (alternatively use water)
Add chocolate to the hot coffee/cocoa mixture. Whisk until chocolate is melted.
¼ Cup Chocolate, bittersweet
Add melted butter and vegetable oil to the bowl. Whisk until combined.
¼ Cup Unsalted Butter, Melted and Cooled, ½ Cup Vegetable or Canola Oil
Add whole eggs and egg yolk to the bowl and whisk until combined.
2 Large Eggs, 1 Large Egg Yolk
Add sugar to the bowl and whisk until combined.
1 ¾ Cups Granulated Sugar
Add flour and salt to bowl. Fold in using a rubber spatula. If pieces of flour are still visible, use a hand whisk to finish mixing the batter.
1 ½ Cups All Purpose Flour, ½ teaspoon Salt
Pour brownie batter into prepared pan. Smooth top with an offset or rubber spatula.
Bake for 15 minutes, rotate pan and bake an additional 10 minutes (25 minutes total).
Remove pan from the oven and set on a cooling rack. Allow the brownies to cool to room temperature (approximately 1 ½ hours). Leave in pan to add topping.