Cook the sweet potato, peel, and mash it.
In a bowl, mix the mashed sweet potato, peanut butter, unsweetened cocoa powder, honey, and baking powder.
Spread the batter evenly in an oven-safe pan.
Bake in a preheated oven at 180°C (356°F) for 25–30 minutes.
Let it cool, slice into pieces, and serve.