Preheat your oven to 350°F (175°C) and prepare two 8-inch round cake pans by greasing them and lining with parchment paper.

Sift together all-purpose flour, baking powder, and salt. In a separate bowl, beat eggs and sugar until pale and thick. Fold in vanilla and lemon zest, then incorporate dry ingredients. Divide batter and bake for 18-20 minutes.

Combine equal parts water and sugar with limoncello in a saucepan over medium heat, stirring until dissolved. Remove from heat and cool.

In a bowl, beat mascarpone cheese, powdered sugar, lemon juice, and vanilla until smooth. Whip cream to soft peaks and fold into the mascarpone mixture.

Once cake layers are cool, slice each in half, brush with syrup, and layer with mascarpone filling. Chill in the refrigerator for at least 1 hour.

Drizzle the limoncello glaze over the chilled cake, dust with powdered sugar, and garnish with lemon slices and mint leaves.