Baked Brunch casserole

I have been making this dish for years.  Every time I make it, I am asked for the recipe.  This can be a breakfast , lunch, brunch or dinner dish.  It goes far, feeds a lot of people and tastes amazing.  I make this very hearty by a secret trick, I use potatoes in the bottom of the dish.  It makes the crust seem even thicker. I like to serve this with a salad and fruit.  Enjoy!

4 pie crusts
5 medium yukon gold baked potatoes cooked and cut into slices
11/2 lbs. ground italian hot and sweet sausage blended equally ( half of each)
2 large vidalia onion sliced and carmelized with 1 t. sugar and 2 T. butter
1 lb. chopped mushrooms
3 cups italian cheese mixture, ( provolone, asiago, and mozzerella and Parmegiano)
8 eggs seasoned with salt and pepper
1 cup whole milk or half and half
3 T. butter
2 T. olive oil
1 egg wisked to glaze top of crust (egg wash)

In large saute pan add olive oil and sausage.  Cook sausage until cooked through. Season with salt and pepper to taste.  Prepare potatoes for baking in the microwave.  Cook potatoes until done.  Set aside when done to cool.  Remove sausage from pan and add in butter, onion slices, sugar and salt and pepper to taste.  Carmelize for 20 minutes.  Remove from pan and set aside.  Add mushrooms and saute until tender.

In medium bowl add the eggs and milk, wisk together and season eggs with salt and pepper.
Spray a 13x9 baking dish with pam.  Roll out 2 pie crusts to fit the bottom on the pan.  Poke fork wholes in bottom of crust and bake on 350 for 10 minutes.  When done crisping up the crust add sliced potatoes to the bottome of the crust covering the entire bottom of the crust.  Salt and pepper the potatoes.  Next layer in the sausage, onions and mushrooms. Top ingredients with cheese mixture.    Pour in the egg and milk mixture.  Top with remaining 2 pie crusts. Poke wholes or slits in top crust and brush on the egg wash.
Bake at 350 until golden brown and cooked through.  Approximately 35 - 40 minutes.

Enjoy!