Preheat oven to 350°F. Line an 8×8-inch baking dish with parchment paper or lightly grease it.
In a medium mixing bowl, combine egg whites, applesauce, vegan protein powder, and baking powder until smooth.
Divide the batter evenly between two bowls. Stir the cocoa powder into one bowl to create the chocolate layer. Stir the peanut powder into the second bowl to create the peanut butter layer.
Spread the chocolate batter evenly into the prepared baking dish, smoothing the top with a spatula.
Carefully spoon the peanut butter batter over the chocolate layer and gently spread it evenly so it covers the surface without fully mixing into the bottom layer.
Bake for 22-28 minutes, or until the center is set and the top feels firm to the touch.
Allow the brownies to cool completely in the pan before lifting out using the parchment paper. Slice into squares or bars.
Store in the refrigerator for up to one week.
If adding the chocolate topping, melt the chocolate chips in a microwave-safe bowl in 20-30 second intervals, stirring between each. Stir in the oil until smooth and glossy. Spread evenly over the cooled brownies and place in the fridge to set before slicing.