Preparation

Step 1: Make the Cupcake Batter

1. Preheat oven to 350°F (175°C) and line a 12-cup muffin pan with cupcake liners.

2. In a large bowl, whisk together coffee, buttermilk, oil, eggs, and vanilla until well combined.

3. In a separate bowl, sift together flour, cocoa powder, sugar, baking soda, baking powder, and salt.

4. Gradually add the dry ingredients to the wet mixture, whisking until just combined. Do not overmix.

Step 2: Prepare the Cream Cheese Filling

1. In a medium bowl, beat the cream cheese with sugar until smooth.

2. Add the egg yolk and vanilla, and mix until creamy and lump-free.

Step 3: Assemble the Cupcakes

1. Fill each cupcake liner about 2/3 full with chocolate coffee batter.

2. Spoon about a teaspoon of cream cheese filling into the center of each cupcake.

3. Gently cover with a tiny bit more cupcake batter if desired (optional for fully hidden filling).

Step 4: Bake

1. Bake in the preheated oven for 18–22 minutes, or until a toothpick inserted at the edge (not center) comes out clean.

2. Let cupcakes cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.

Step 5: Make the Swirled Buttercream Frosting

1. Beat the butter until fluffy and pale.

2. Gradually add powdered sugar and beat until light and smooth.

3. Add vanilla, a pinch of salt, and cream/milk as needed to reach desired piping consistency.

4. Divide frosting into two bowls. Leave one plain (vanilla), and mix cocoa powder into the other for the chocolate swirl.

5. Fill a piping bag with both frostings side-by-side to create a beautiful swirl effect.