Retro Chocolate Cupcakes with a sweet mascarpone center

Preheat oven to 350° with a rack in the center. Line a muffin pan with cupcake liners.

For the cupcakes, cream butter and sugar with a hand mixer on medium-high speed until light and fluffy, 3–5 minutes. Add eggs, one at a time, beating well after each addition; beat until smooth and silky. Add vanilla and beat until well combined; scrape down sides of bowl as necessary.

Whisk together flour, cocoa, and salt in a bowl. Add flour mixture to butter mixture in thirds, alternating with buttermilk; begin and end with flour.

Pour vinegar into a measuring cup and add baking soda (if you do it the other way around, it foams a lot); whisk into batter mixture.

Fill each cupcake liner three-quarters full with batter. Bake cupcakes until a toothpick inserted into centers comes out clean, 25–28 minutes. Cool cupcakes in pan 10 minutes; remove from pan and cool completely on a rack.

For the filling, cream butter and mascarpone with a hand mixer on medium-high speed until fluffy, 2–3 minutes. Add sugar and salt; continue beating until fluffy, 1–2 minutes.

Fill a piping bag fitted with a large tip with filling. Poke pastry tip through the top and into centers of cupcakes, squeezing about 2 Tbsp. filling into each.

For the chocolate icing, heat cream in a small saucepan over medium to almost boiling. Remove pan from heat, add chocolate, and stir until chocolate is melted and well combined. Add vanilla, stirring constantly. (If making in advance, cover with plastic wrap and set aside until ready to ice the cupcakes. But note — icing is best made right before icing them.) Use an offset spatula or back of a spoon to spread a thin, flat layer of icing over the tops of the cupcakes. (Or you can hold the cupcakes from the bottom and “swirl” the tops in the icing.) Let icing set completely before decorating with royal icing.

FOR ROYAL ICING

Mix 2 tsp. light corn syrup and 2 tsp. heavy cream (or milk) in a small bowl. Add 1 cup confectioner’s sugar and mix with a fork until creamy and smooth. If icing is too thick, add a little more corn syrup and cream. If it’s too thin, add a little more sugar. (Icing should be thick enough not to bleed or spread when piped.) Place icing in a piping bag fitted with a small tip, and pipe cursive lowercase e’s down the center of each cupcake.