Grease and flour 3 8” round cake pans; set aside. Preheat oven to 325°F.

In a medium bowl, sift together the cake flour, baking powder and salt; set aside.

In a separate bowl, whisk together the milk, sour cream and vanilla extract; set aside.

Using a countertop mixer fitted with the paddle attachment, cream together the butter and sugar until light and fluffy (~3-4 minutes on medium-high speed).

Add about half of the flour mixture to the bowl; mix on low speed until well combined.

Add the milk mixture to the bowl. Mix on low until well combined.

Add the remaining flour mixture; mix on low until well combined. (Tip: Don’t forget to scrape down the sides of the bowl to ensure all ingredients are fully mixed.)

In a separate bowl, beat egg whites on medium speed until stiff peaks form. Carefully fold the egg whites into the cake batter until fully mixed.

Divide the batter evenly between the 3 cake pans. Bake at 325°F for 30-32 minutes, or until a toothpick inserted into the center of the cake comes out clean.

Whisk all ingredients together in a medium bowl; set aside.

Using a countertop mixer, cream the mascarpone cheese and powdered sugar until light and fluffy (~2-3 minutes on medium-high speed).

Add the rum and vanilla; beat on low until fully incorporated.

In a separate bowl, whip the cream on high speed until stiff peaks form. Carefully fold the whipped cream into the mascarpone mixture until well combined.

Allow cake layers to cool for ~20 minutes before assembling.

Place one layer of cake on a large plate. Brush the top with ⅓ of the Espresso Syrup. Spread ~1 cup of Frosting evenly over top of layer. Repeat this process with the remaining two layers of cake.

Use remaining frosting to frost top and outside of cake.

Using a fine-mesh sifter, gently sift the cocoa powder onto the top of cake.

To garnish, whip the remaining cream until stiff peaks form. Place whipped cream in a large piping bag fitted with a large star tip. Pipe ring of whipped cream around the edge of the top of the cake.

Gently press the ladyfingers into frosting on sides of cake.