Tarta de Ricota con Dulce de Leche

Name: Tarta de Ricota con Dulce de Leche
Ingredients: Sugar Crust; 5 tablespoons very cold unsalted butter; 2/3 cup all purpose flour; 1/3 cup whole wheat pastry flour (or all purpose+1 tbsp extra); 1/4 teaspoon salt; 3 tablespoons white sugar; 1 large egg yolk; 2 tablespoons milk or cream; Ricotta Dulce de Leche Filling; 2 large egg whites; 1/4 cup white sugar; 1 1/4 cups whole milk ricotta; 1/4 cup milk; 2 large egg yolks; 3 tablespoons all purpose flour; 1 teaspoon baking powder; 1/2 cup dulce de leche; confectioner sugar for dusting (optional)