Preheat oven to 275 F for a metal pan or 350 F for glass.
Roll out pastry dough and transfer to a 9-inch quiche dish or pie pan. Ease dough onto bottom and sides; prick the bottom and sides with a fork.
Partially bake until the crust just starts to get some color, about 12-15 minutes. Let cool slightly.
While the crust is baking, in a large bowl beat the eggs and half and half lightly. Add salt, pepper, marjoram, onion, green pepper, mushrooms, and collard greens. Set aside.
In a small bowl, mix cheeses together. Sprinkle half the cheese onto the piecrust and add the remaining cheese to the egg mixture.
Add the egg mixture to the piecrust; top with more cheese if desired.
Bake until a knife can be inserted near the center and come out clean, about 45-60 minutes. Let sit 10 minutes before cutting into wedges.
Quiches are one of those dishes that are super customizable. Don't like green peppers? Leave them out. Have extra tomatoes or spinach in the fridge? Add them! Bacon or ham are also great additions. Add your own favorite spices and cheeses too, or whatever you have on hand.