Preheat your oven to 350°F (175°C) and grease and flour two 9-inch round cake pans.

In a mixing bowl, combine the flour, baking powder, baking soda, and salt. Whisk together until well mixed.

In another bowl, cream the softened butter and sugar together until light and fluffy (about 3-5 minutes).

Add in the eggs, one at a time, mixing well after each addition, followed by the vanilla extract.

Gradually add the dry ingredients to the butter mixture, alternating with the buttermilk, until everything is just combined. Be careful not to overmix!

Stir in the lemon zest and fresh lemon juice for that zesty kick.

Divide the batter evenly between the prepared pans and smooth out the tops.

Bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean.

Allow the cakes to cool in the pans for 10 minutes before transferring them to a wire rack to cool completely.

In a mixing bowl, whip the heavy cream until soft peaks form.

In a separate bowl, beat the mascarpone cheese until smooth. Gradually add the powdered sugar and continue to beat until well combined.

Gently fold the whipped cream into the mascarpone mixture, incorporating the vanilla extract and lemon zest until you have a smooth frosting.

Once the cakes are completely cool, place one layer on a serving platter.

Spread a generous amount of the mascarpone frosting over the top of the first layer.

Place the second cake layer on top and frost the top and sides of the cake with the remaining mascarpone frosting.

For an added touch, decorate with fresh berries or lemon zest if desired.

Slice and serve, enjoying each bite of this delightful Limoncello Mascarpone Cake!