Lemon Filling:
3 egg yolks (reserve whites for meringue)
3/4 cup granulated white sugar
3 tbsp. all-purpose flour
pinch of salt
3 tbsp. lemon juice
2 tbsp. lemon zest, loosely packed
1/2 cup water
2 tbsp. unsalted butter, melted

Cupcakes:
1/2 cup unsalted butter
1 cup sugar
2 eggs
3 tbsp. lemon juice
2 tsp. baking powder
1 tsp. salt
1-1/2 cups all-purpose flour

Meringue:
3 egg whites
pinch of salt
1/4 cup sugar