This is my go-to recipe for quiche. I've made it using frozen and refrigerated crusts and hope to someday make a homemade crust. It always turns out great. Any shredded cheese works...cheddar, swiss, Gruyere. I usually use a medium cheddar because it is what I have on hand.

(Picture from http://www.mysuzyhomemaker.com/)
-2 cups shredded cheese
-1 package frozen, chopped spinach
-1 onion, chopped
-3-5 cloves of garlic, chopped
-2 frozen pie crusts, 2 refrigerated pie crusts, or homemade pie crust
-4-5 Eggs
-2 cups heavy cream, half and half, whole milk, or 1 % milk, (I use whatever I have and they all work great)
-3/4 tsp salt
-fresh ground pepper
Preheat oven to 350 degrees. Thaw and cook frozen spinach. Make sure you squeeze most of the water out, (paper towels work good here). Saute onions and garlic in olive oil until caramelized. Put one cup of cheese in each pie crust or two cups of cheese in a 9x13" pan with pie crust already on bottom. Spread onion and garlic mixture on top of cheese. Spread spinach on top of onions. Whisk together eggs, cream, salt, and pepper in a medium bowl. Pour custard on top of veggies. Bake for 45 minutes or until knife comes out clean. Let sit 15 minutes before slicing. Refrigerate leftovers. Double wrap extra quiche and freeze.