Preheat the oven to 350°F.
In a large bowl, melt the vegan butter and ¼ cup of the chocolate chips in the microwave for about 45 seconds.
Stir in the cane sugar while the melted butter and chocolate is still hot. Set this bowl aside to cool down for 5 minutes while preparing the other parts of the recipe.
In a medium-sized bowl, pour in the flour, cocoa powder, baking powder, and salt through a sifter to break up the clumps. Then stir them together.
Grease an 8x8 dish with vegan butter or oil. You can also line it with parchment paper for easy removal of the brownie block later.
Mash the bananas and measure out exactly 1 cup of them. Stir them into the melted chocolate bowl along with the vanilla extract.
Add the dry ingredients to the wet-ingredient bowl. Gently combine everything together. Fold in the chocolate chips and chopped nuts.
Pour the brownie batter into the dish and use a spoon to spread it out. Bake it for about 30 minutes. They are ready when the edges start to pull away from the dish and a toothpick comes out mostly clean. A few moist crumbs or melted chocolate on the toothpick are just fine.
Let them cool down for 10 minutes to allow time for them to set.