01 - Preheat oven to 350°F. Line an 8-inch square baking pan with parchment paper, leaving an overhang to facilitate removal.
02 - Whisk almond flour, cocoa powder, baking powder, and salt in a medium bowl until evenly mixed.
03 - In a large bowl, whisk melted butter with granulated and brown sugars until smooth. Add eggs and vanilla extract and whisk until fully incorporated.
04 - Gradually add the dry mixture to the wet ingredients, stirring gently until just combined. Fold in chocolate chips and nuts if using.
05 - Transfer batter into prepared pan and smooth the surface as evenly as possible with a spatula.
06 - Bake for 23 to 25 minutes, or until a toothpick inserted in the center comes out with moist crumbs but no wet batter.
07 - Let brownies cool completely in the pan on a wire rack. Use parchment overhang to lift brownies, slice, and serve.