Preheat your oven to 350°F (175°C). Line your baking pan with parchment paper, allowing some overhang for easy removal later.
In a microwave-safe bowl, combine the vegan dark chocolate chunks and cold coconut cream. Heat in the microwave in 30-second intervals, stirring between each, until the chocolate is completely melted and smooth.
In a separate bowl, whisk together the unbleached all-purpose flour, salt, and baking powder. Set aside.
In another bowl, mix the mashed overripe banana, egg replacer (prepared with water), vanilla extract, sugar, and instant espresso/coffee powder. Beat well until combined.
Gradually fold the melted chocolate mixture into the wet ingredients, mixing until smooth. Then, slowly add in the dry ingredients and gently fold until just combined; be careful not to overmix.
Fold in the thinly sliced ripe banana, ensuring the slices are evenly distributed throughout the batter.
Pour the brownie batter into the prepared baking pan and spread it evenly. Bake for 25-30 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.
Allow the brownies to cool in the pan for about 10 minutes, then lift them out using the parchment paper. Let them cool completely on a wire rack before slicing into squares.
