Preheat your oven to 350°F (177°C). Prepare two 6-inch round cake pans by greasing them generously with butter and lining with parchment paper.

In a medium bowl, sift together 1 ½ cups of cake flour, 2 teaspoons of baking powder, and a pinch of salt. Set aside.

In a small bowl, combine 2 tablespoons of instant espresso powder with 1 cup of boiling water. Stir until dissolved and allow to cool.

Using a stand mixer, beat together ½ cup of softened unsalted butter and 1 cup of sugar until light and fluffy, about 3-4 minutes.

Add the eggs one at a time, then blend in 1 teaspoon of vanilla extract until smooth.

Alternately add the flour mixture and ¾ cup of whole milk to the butter mixture, mixing gently after each addition. Fold in the cooled espresso.

Divide the batter between the prepared pans and bake for approximately 20 minutes, until a toothpick comes out with a few moist crumbs.

Let the cakes cool in their pans for about 10 minutes, then transfer to a wire rack to cool completely.

In a mixing bowl, whip together 8 ounces of cold mascarpone cheese until creamy, then gradually add 1 cup of sifted powdered sugar and mix until smooth. Fold in 1 cup of heavy whipping cream until light and fluffy.

Once the cake layers have cooled, slice each layer in half horizontally. Soak with liquor or additional coffee, frost between layers, and dust the top with cocoa powder.