- Allow butter and eggs to stand at room temperature for 30 minutes. Grease twelve 2 1/2-inch muffin cups or line with paper bake cups; set aside. In a medium bowl stir together flour, baking powder, baking soda, and salt; set aside.
- Preheat oven to 350 degrees F. In a large bowl beat butter with an electric mixer on medium to high speed for 30 seconds. Add 2/3 cup sugar and the vanilla. Beat on medium to high speed about 2 minutes or until light and fluffy, scraping sides of bowl as necessary. Add eggs, one at a time, beating after each addition until combined. Alternately add flour mixture and buttermilk to butter mixture, beating on low speed after each addition just until combined. Stir in the 1/2 cup chocolate pieces.
- Spoon batter into prepared muffin cups, filling each cup about half full. Bake for 18 to 20 minutes or until a wooden toothpick inserted in the centers comes out clean. Cool cupcakes in muffin cups on wire racks for 5 minutes. Remove cupcakes from muffin cups. Cool on wire racks for 10 minutes.
- Meanwhile, in a small bowl stir together hot espresso and the 2 tablespoons sugar until sugar is dissolved; cool and stir in rum. Using a bamboo skewer or toothpick, poke about eight holes into the top of each cupcake, inserting the skewer about halfway down. Spoon 1 to 1 1/2 tablespoons of the espresso mixture evenly over each cupcake; let it absorb into cupcakes. Cool cupcakes completely.
- Frost cupcakes with Mascarpone Frosting. Dust with cocoa powder. If desired, garnish with raspberries, additional chocolate pieces, and/or shredded chocolate. Chill for at least 30 minutes or up to 24 hours before serving.
From the Test Kitchen
To make 1/3 cup sour milk, place 1 teaspoon lemon juice or vinegar in a glass measuring cup. Add enough milk to make 1/3 cup total liquid; stir. Let stand for 5 minutes before using.
You can also substitute unfrosted purchased cupcakes or use a mix for the cupcakes. If the mix makes, 24 cupcakes, double the espresso-rum mixture, the Mascarpone Frosting, and the cocoa powder.
- In a chilled large bowl beat the whipping cream, powdered sugar, and vanilla until soft peaks form (tips curl). In a small bowl, fold 1/4 of the whipped cream into the mascarpone cheese. Fold the mascarpone mixture into the remaining whipped cream until incorporated. If desired, fold in dark rum, coffee liqueur, or brandy.
Nutrition Facts (Tiramisu Cupcakes)
- Per serving:
- 368 kcal ,
- 25 g fat
- (14 g sat. fat ,
- 1 g polyunsaturated fat ,
- 5 g monounsaturated fat ),
- 97 mg chol. ,
- 166 mg sodium ,
- 32 g carb. ,
- 1 g fiber ,
- 21 g sugar ,
- 5 g pro.