Pastelon de Berenjena y Queso Recipe (Eggplant & Cheese Casserole)

Ingredients
Oil or butter for greasing the pan
3 tablespoons of butter
4 tablespoons of all-purpose flour , sifted
1 1/2 cups of whole milk (or milk substitute)
1 teaspoon of salt (or more, to taste)
1/2 cup of grated mozzarella cheese
4 large eggplants sliced thinly
1/2 cup of grated parmesan cheese

Instructions
Heat oven to 350 °F [180ºC]. Grease a mid-sized baking pan.
In a saucepan heat the butter over low heat. Add the flour and stir vigorously until the two are well mixed. Add the milk and stir until it reaches a uniform consistency. Add a pinch of salt and keep stirring until it becomes a thick cream. Add the mozzarella cheese and mix. Taste and add more salt to taste if needed. Set aside.
Lay a layer of eggplants on the baking pan and spread some of the sauce that you had prepared previously. Keep adding layers of eggplants, “glueing” each layer with the sauce. Cover with a final layer of eggplant. Cover the baking pan with tinfoil and bake for 40 minutes.
Uncover, sprinkle with the parmesan cheese and bake until the top is light golden.