Preheat oven to 350 degrees Fahrenheit.

In a bowl, mix together the flour, cocoa powder, baking powder, sugar, coffee, eggs, vanilla extract, and oil (by hand) until a dough forms. Press evenly over the bottom of a 9×13-inch pan.

Bake for 15 minutes (a toothpick inserted in the center will come out with some crumbs). Remove from the oven and set aside to cool.

If your peanut butter is too firm to spread easily, microwave it for 30–40 seconds, stirring every 10 seconds. Spread evenly over the cake and set aside until fully set.

In the microwave, melt the chocolate with the oil and mix until completely smooth. Pour over the peanut butter and let cool.