Preheat the oven to 350 degrees F (180 degrees C).
Arrange the 9-inch Pie Crust (1) in a pie pan, pressing firmly on the bottom and sides of the pan. Fold any overhanging edges of the pastry under itself and using your fingers or the tines of a fork, press the edges to form a decorative rim.
Squeeze all the excess moisture from the Frozen Spinach (10 ounce) and set aside.
If you have a high-powered professional blender (like a Vitamix) place the Egg (4), Half and Half (1 cup), Ground Nutmeg (1/4 teaspoon), and spinach in the blender and turn on low, gradually increasing the speed until emulsified and bright green.
Without a blender: Finely chop the spinach. Whisk the eggs and half and half in a large bowl until well combined, then stir in the spinach, nutmeg, salt and pepper. Stir until well combined and proceed with the recipe.
Pour the mixture into a large bowl. Season with Kosher Salt (1/2 teaspoon) and Ground Black Pepper (1/4 teaspoon).
Stir in 1 cup of the Gruyère Cheese (1 cup).
Transfer the spinach mixture to the pastry shell.
Sprinkle with the remaining grated Gruyère Cheese (1/4 cup) and grated Parmesan Cheese (2 tablespoon). Bake for 40-45 minutes or until quiche is set.
Let cool for 20 minutes before cutting. Serve and enjoy!