Step 1: Make the Cakes

1. Preheat the oven to 350°F (175°C). Line two cupcake tins with paper liners.
2. In a mixing bowl, whisk together the flour, baking powder, and salt. Set aside.
3. In another bowl, cream the butter and sugar until light and fluffy. Beat in eggs, one at a time. Add vanilla extract.
4. Gradually add the dry ingredients, alternating with the milk, and mix until just combined.
5. Fill cupcake liners 2/3 full and bake for 18-20 minutes or until a toothpick inserted into the center comes out clean. Cool completely.

Step 2: Make the Coffee Soak

1. Mix coffee liqueur, espresso powder, sugar, and hot coffee until the sugar dissolves.
2. Remove cupcake liners and quickly dip the bottoms of each cupcake into the coffee soak (less than 1 second). Place on a tray to rest.

Step 3: Make the Frosting

1. Whip heavy cream until soft peaks form. Add cornstarch and confectioners’ sugar; beat until stiff peaks form.
2. Gently fold in mascarpone and vanilla extract until smooth.

Step 4: Assemble and Garnish

1. Pipe the frosting onto cooled cupcakes using a piping bag with a pastry tip.
2. Dust the tops with cocoa powder and garnish with chocolate shards or shavings.