Cupcakes

375 g cake flour
1 tablespoons baking powder
1/2 teaspoon salt
226,8 g butter, at room temp
1 lemon zested
300 g sugar
5 eggs
295 ml milk
2 tablespoons lemon juice

Filling

6 tablespoons unsalted butter, at room temp
200 g sugar
2 egg
2 egg yolks
2/3 cup fresh squeezed lemon juice
1 teaspoon grated lemon zest

Frosting

437,5 g powdered sugar
113 g unsalted butter, at room temp
3 tablespoons (44 ml) milk
1 teaspoon vanilla extract
2 tablespoons (30 ml) lemon juice
1 teaspoon lemon zest