Beat the egg whites, then fold in the yolks until they're fully mixed.
Add the sugar and mix until incorporated.
Add the flour, baking powder and lemon zest, and mix together by hand.
Pour into a pan lined with buttered parchment paper and bake in a 350°F oven for ten minutes.
Mix the lemon juice with three tablespoons of powdered sugar.
Stamp out the cakes with cookie cutters the size of the pan you're going to use.
Add one layer of the cake to the pan and brush with the lemon sauce.
Add a layer of dulce de leche.
Add another cut layer of the cake on top, brush with more lemon sauce, and add another layer of dulce de leche.
Add last layer of cake on top.
Dust with powdered sugar.