Chocolate Peanut Butter Mini Cake

Preheat oven to 350°F. Grease and line a 6-inch cake pan with parchment paper.

Whisk together flour, cocoa powder, baking powder, espresso powder, and salt. In a separate bowl, whisk oil, sugar, egg, vanilla, and milk until smooth.

Add the dry ingredients to the wet ingredients and mix just until combined. Pour into the prepared pan and bake for 30–35 minutes, or until a toothpick comes out with a few moist crumbs.

Cool in the pan for 10 minutes, then transfer to a rack and cool completely.

For the frosting, beat butter until creamy. Add powdered sugar and beat until combined. Mix in peanut butter and vanilla, then add milk or cream and beat until smooth and fluffy.

Frost the cooled cake, slice, and enjoy.