Line the mold with baking paper and preheat the oven to 175 ° C (convection 160 ° C).
Beat the butter with the peanut butter until creamy. Thoroughly stir in the sugar, then stir in the eggs (one at a time). Mix flour with baking powder and stir in.
Pour the batter into the mold, smooth it out and sprinkle with peanuts. Bake for 30-35 minutes so that the surface is crispy and the inside is soft.