• Preheat the oven to 350°F/175°C. Grease and line two 8-inch round cake pans with parchment paper.
• In a small bowl whisk together all-purpose flour, baking powder and salt. Set aside.
• In a large bowl add granulated sugar and lemon zest. Use your fingers to rub the zest into the sugar to release the lemon oil.
• Add in softened butter and use an electric mixer (or use the bowl of a stand mixer fitted with a paddle attachment.)
• Beat it until the mixture is light and creamy.
• Add in the eggs, vanilla, flour mixture and milk.
• Beat it together on low-medium speed until the batter is cohesive and creamy, around 25-30 seconds.
• Divide the cake batter evenly over the cake pans.
• Bake for around 22-24 minutes until the tops of the cakes spring back when lightly pressed, or a cake tester inserted comes out clean.
• Let the cakes cool in their pan for 10 minutes before removing them and cooling them further on a wire rack.

Frosting

• In a medium bowl add the mascarpone, powdered sugar, vanilla and salt.
• Using a hand mixer at high speed, whisk it until combined.
• Turn the mixer on low speed and slowly stream in the heavy cream. Once the cream is incorporated, turn the mixer to medium-high speed and mix until it is thick and forms stiff peaks. Once thick, stop mixing or the mixture will split.
• Place a cooled cake layer on a plate or cake stand. Dollop half the mascarpone mixture on top of the cake. Use the back of a spoon to spread it out.
• Add on lemon curd and swirl the curd into the cream mixture. Add the second cake layer and repeat with the remaining cream and lemon filling.