Chocolate-Peanut Butter Cupcakes

Adjust oven rack to lower-middle position and heat oven to 400 degrees. Line a 12-cup muffin tin with cupcake papers; spray with vegetable cooking spray.

Whisk flour, baking soda, and salt in a medium bowl; set aside. Measure cocoa and coffee in a medium bowl. Whisk in water to form a smooth thick paste. Stir in sour cream and vanilla; set aside.

With a hand mixer, beat butter and sugar until light and fluffy. Beat in eggs, one at a time. Starting and ending with dry ingredients, alternate adding chocolate mixture and flour, beating until each is thoroughly incorporated.

Evenly divide batter among prepared muffin cups. Bake until fully cooked and golden, about 20 minutes. Remove from oven, let cupcakes stand a couple of minutes; turn onto a wire rack to cool.

Meanwhile, whisk peanut butter into frosting; spread a portion over each cupcake. Garnish with peanut butter cup quarters. Serve.