Preheat oven to 350°F (175°C). Grease and line two 8-inch round cake pans.

Make the cake: In a bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.

In a large bowl, beat butter and sugar until light and fluffy. Add eggs one at a time, then stir in vanilla.

Mix in the flour mixture in three parts, alternating with milk and coffee. Mix until just combined.

Divide batter between pans and bake for 25–30 minutes or until a toothpick comes out clean.

Let cakes cool in pans for 10 minutes, then transfer to wire racks to cool completely.

Make the coffee soak: Combine espresso and coffee liqueur. Set aside.

Make the frosting: In a bowl, whip heavy cream until stiff peaks form. In another bowl, beat mascarpone, powdered sugar, and vanilla until smooth. Fold in whipped cream gently until combined.

Assemble the cake: Place one cake layer on a plate. Brush generously with coffee soak. Spread a thick layer of frosting on top.

Add second cake layer, brush with more soak, and frost the top and sides of the cake.

Finish: Dust with cocoa powder and decorate with chocolate shavings or coffee beans if desired.

Chill for at least 2 hours before serving for best flavor and texture.