Preheat oven to 200C/ 390F. Use a fork to poke a few wholes into your sweet potato - now bake it with the skin on, until tender.
Let the sweet potato cool down.
Now peel the sweet potato, add it to a bowl along with peanut butter and mix well.
Add the rest of the ingredients and mix again. Make sure the espresso shot is cold, if not, the chocolate will melt.
Pour the batter into an oven proof dish, and bake for 35-40 minutes on 175C/ 350F.
