Ingredients for 6 to 8 people:

For the base:
Unbleached flour, between 1 1/2 and 2 cups
Unsalted butter, 1/3 cup
Salt, 1/2 teaspoon
Water, as needed

For the filling:
Frozen chopped spinach, 10 oz
Ricotta cheese, 15 oz
Egg, 1
Nutmeg
Salt, 1 teaspoon

Preparation:
In a bowl mix the ingredients for the base, adding a little water at a time. The dough must be soft, not soggy. Make a ball with the dough, divide into 2 pieces (a small and a slightly bigger one) and let rest in a cool place while you prepare the filling.

Defrost the spinach in the microwave or by steaming them and let them cool down. Beat the egg, add the ricotta cheese, salt, and nutmeg. Add the spinach and mix well. With the bigger piece of dough, make a flat disk and place it in a greased round glass baking pan. Fill it with the spinach mixture.
With the other piece of dough make another flat disk and cover the mixture, making sure to overlap the two edges of the disks and to seal them pressing with your fingers.
With a fork make a few holes on the top of the pie so that the steam will not be trapped inside. If you want to give the crust a nice brown-golden color, brush the top disk with egg white or milk.

Bake in the oven at 350-375 degrees for 40-45 min (or until the upper and lower crusts are golden brown).