To prepare a gluten free vegan dark chocolate brownies recipe, first you need to prepare the brownie batter. First, you'll need the following ingredients: 14 cup of cocoa powder, 1 tablespoon of sugar, 2 tablespoons of vegetable oil, and 1 teaspoon of vanilla extract. Mix the ingredients together until they're well combined. Pour the batter into the prepared pan and bake for 20 minutes at 325 degrees F. Remove from the oven and let cool for 5 minutes before cutting into squares.