01 -  Preheat oven to 350°F. Line an 8x8-inch baking pan with parchment paper. 
 02 -  Whisk flour, cocoa powder, baking powder, and salt together in a medium bowl. 
 03 -  In a large bowl, blend nut-milk pulp, sugar, melted coconut oil (or unsalted butter), eggs, and vanilla extract until smooth and homogenous. 
 04 -  Gradually fold dry ingredients into wet mixture, mixing just until incorporated. Avoid overmixing. 
 05 -  Gently stir in chocolate chips and nuts, if desired. 
 06 -  Transfer batter to prepared baking pan, smoothing the surface evenly. 
 07 -  Bake for 28 to 32 minutes, or until a toothpick inserted near the center yields a few moist crumbs. 
 08 -  Allow the brownies to cool completely in the pan. Slice into squares for serving.