Preheat the oven to 375°F. If using a homemade pie crust, press into a 9 inch deep dish pan. Crimp edges as desired. If using a frozen or homemade crust, place onto a baking sheet for easy moving in and out of the oven.
In a small mixing bowl, whisk together heavy cream, eggs, chopped parsley, onion powder, salt, pepper, garlic powder, dry mustard and nutmeg.
To assemble: Arrange diced ham evenly over bottom of pie crust. Sprinkle Parmesan cheese over ham. Sprinkle 1 cup of shredded Swiss or Gruyere over Parmesan.
Arrange chopped spinach over shredded cheese. Pour the filling evenly over the spinach layer making sure it's evenly distributed. It's helpful to use a fork to gently move spinach in places to allow it to reach ham. Sprinkle the remaining shredded Swiss cheese on top.
Place into the preheated oven and bake for 30-40 minutes until spinach is tender and egg custard is cooked through.
Allow the quiche to stand on the counter for at least 20 minutes before serving.
Should you choose to use Pillsbury or a similar brand of refrigerated crusts for this quiche, I recommend using both rolled together to form a thicker pie crust.