For the Filling
8 oz mascarpone room temp 227g
1/2 cup whipping cream cold 125mL
1/4 cup powdered sugar 25g
1 tsp vanilla extract 5mL
3 tbsp lemon zest
For the Frosting
4 egg whites large
1 1/2 cups sugar 150g
1 pound butter room temp 454g
3 tablespoons grated lemon zest