Cover the dough with a towel, and let the dough come to room temperature. Allow to rise in a warm place for about 45 minutes.
Knead in the Parmesan cheese, and cut into two pieces, one slightly smaller than the other. Cover and set aside to rise.
In a medium skillet over medium-high heat, sauté garlic in olive oil for 30 seconds.
Squeeze the drained spinach in a lint-free towel to get as much liquid out as possible. Add spinach to the skillet, and sauté only until spinach wilts.
Stir in fresh nutmeg and salt and pepper to taste. Set aside.
Stir together tomato and basil, along with a pinch of salt and a grind or two of black pepper. Set aside.
Roll the larger half of the dough out as thin as you can. You might have to stop and let the dough rest a few minutes if it starts springing back. Just cover it with a towel for about ten minutes to let the gluten relax.
Fit the dough into the spring form pan and up the sides, allowing about 1/2 inch to overhang.
Begin layering the ingredients in this order: ½ cup of the mozzarella, sautéed spinach, all the provolone, tomato and basil mixture, the meat, and the remaining mozzarella.
Roll out remaining dough and place it on top of the pie and seal edges together. Set aside and let rise for 1 hour.
Preheat oven at 375°.
Brush egg and water mixture evenly on top of the pie.
With a sharp knife, cut three or four slits in the dough to allow steam to escape.
Bake in the lower ⅓ of the oven until the crust is a deep golden brown, about 40 minutes.