Follow these easy steps to create your Limoncello Mascarpone Cake:

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

2. Mix Dry Ingredients: In a large bowl, sift together the flour, baking powder, and salt. Set aside.

3. Cream Butter and Sugar: In another bowl, cream the softened butter and granulated sugar until light and fluffy.

4. Add Eggs: Beat in the eggs one at a time, ensuring each is well incorporated before adding the next.

5. Combine Mixtures: Gradually mix in the dry ingredients, alternating with milk. Stir until everything is just combined.

6. Flavor It: Add limoncello, lemon zest, and vanilla extract into the batter, mixing until fully integrated.

7. Divide Batter: Pour the batter evenly into the prepared pans, smoothing the tops if necessary.

8. Bake: Bake in the preheated oven for 25-30 minutes or until a toothpick inserted into the center comes out clean.

9. Cool the Cakes: Remove from the oven and let the cakes cool in the pans for 10 minutes. Then transfer them to wire racks to cool completely.

10. Prepare the Mascarpone Frosting: In a mixing bowl, combine mascarpone cheese, heavy cream, powdered sugar, limoncello, and lemon zest. Beat until thick and fluffy.

11. Assemble the Cake: Once the cakes are completely cool, place one layer on a serving platter. Spread a generous layer of mascarpone frosting on top.

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

13. Chill and Serve: Refrigerate the cake for about 30 minutes to set the frosting before serving.