Hearty breakfast quiche

I would compare this casserold to a quiche, sort of? Anyway, I made it this Winter for a Christmas thing and it was a huge hit.  Very hearty and filling, with veggies and all sorts of surprises in there too.  We have a pig in the freezer as you all know, so we have an abundance of pork sausage I need to dispose of (and don't like to eat all by myself)....so this recipe is good for getting rid of that.  Plus, it's great to have a breakfast casserole ready to throw in the oven when we have people over, that way I don't have to cook in the morning.

1 lb pork sausage (could use turkey sausage as well)

1/2 cup chopped onion (I leave this out depending on who is going to eating it)

1 and 1/2 cups shredded cheese (I used 2% mexican cheese)

1 (10 oz package) frozen chopped spinach, thawed and drained

1 can sliced mushrooms

12 eggs

2 cups heavy cream (I used skim milk)

In a skillet, cook sausage and onion, until the sausage is browned and the onion is tender.  Drain, and spread in the bottom of your baking dish (greased with fat free Pam).  In a large mixing bowl, mix the spinach, half the cheese, mushrooms, eggs, and cream together, beating the eggs.

Pour over the sausage in the pan.  Cover and throw in the fridge until the next morning, careful moving it around as it's very liquid at this point. 

Bake uncovered at 350 degrees or until a knife comes out clean from the center (like a cake).  Sprinkle with remaining cheese, and let sit for 5 minutes before serving so it all melts.  I promise you will get Wow's from this and will seem like you spent hours in the kitchen preparing a breakfast quiche!  I didn't get any pics of this in the morning...I am soooooo not a morning person.