01 - Preheat oven to 350°F. Grease and flour two 8-inch round cake pans.
02 - In a large bowl, beat butter and granulated sugar together until light and fluffy. Add eggs, one at a time, beating well after each addition.
03 - Mix in lemon zest, lemon juice, and vanilla extract until fully incorporated.
04 - In a separate bowl, whisk together flour, baking powder, and salt.
05 - Add dry ingredients to the wet mixture in three parts, alternating with milk, beginning and ending with flour. Mix until just combined.
06 - Divide batter evenly between prepared pans. Smooth the tops. Bake for 25–30 minutes or until a toothpick inserted in the center comes out clean.
07 - Let cakes cool in pans for 10 minutes, then turn out onto wire racks to cool completely.
08 - Beat mascarpone and powdered sugar until smooth. Add lemon juice, lemon zest, and vanilla.
09 - In a separate bowl, whip cream to stiff peaks. Gently fold whipped cream into mascarpone mixture until fully combined.
10 - Once cakes are cool, place one layer on a serving plate. Spread with half the lemon cream. Top with the second cake layer and spread remaining cream on top and sides.
11 - Chill cake for at least 1 hour before serving. Dust with powdered sugar and garnish with lemon slices or zest before serving.