01 - Preheat oven to 350°F. Line an 8x8 inch baking pan with parchment paper, allowing overhang for easy removal.
02 - In a medium bowl, whisk together flour, cocoa powder, brown sugar, baking powder, and salt until well combined.
03 - Pour melted coconut oil or vegan butter, plant milk, and vanilla into the dry ingredients. Mix until just combined, then fold in 1/2 cup vegan dark chocolate chips.
04 - Transfer brownie batter to the prepared pan. Spread evenly using a spatula, creating a smooth base layer.
05 - In a separate bowl, beat softened vegan butter, brown sugar, and granulated sugar until light and fluffy, approximately 2 minutes.
06 - Add plant milk and vanilla to the butter mixture. Stir in flour, baking soda, and salt until just combined. Fold in 3/4 cup vegan chocolate chips.
07 - Carefully spread cookie dough over the brownie batter. Lightly wet your hands or spatula with water to prevent sticking and achieve an even layer.
08 - Bake for 30 to 35 minutes until golden brown on top. A toothpick inserted in the center should emerge with a few moist crumbs.
09 - Cool completely in the pan, approximately 1 hour. Lift using parchment paper overhang and cut into 12 equal squares.