Spinach, red Pepper and Feta Quiche

This is a great recipe to have on hand for improvising based on what you have on hand.
You definitely need to double the eggs and cream/milk, otherwise you don't have enough batter to cover everything. I'll admit that I always use a frozen crust, so can't comment on that part of the recipe.
I've made it with the ingredients as written, but also substituted different fillings (mushrooms, tomatoes, pancetta) cheeses based on what I have on hand.