Preheat oven to 350°F (180°C) and fold a 7x7 in (15 cm x 15 cm) brownie pan with parchment paper.
In a bowl, combine the pureed pumpkin with almond butter, maple syrup and cocoa powder. If you plan to include some mix-ins, add them now. Using a whisk or fork, stir well until you get a smooth batter.
Transfer the brownie batter to the prepared brownie pan and spread it out evenly with the help of a spatula.
Bake in hot oven for 25 to 30 minutes, or until they are no more raw inside. Let cool completely at room temperature before slicing.
