Breakfast Scrambled Egg Casserole

Description
This recipe came from an estate sale. I obtained it when I purchased the family collection from the Hager Estate in Canton, Texas in 1982.
 * Contributed by Catsrecipes Y-Group

Ingredients

 * ½ cup butter
 * 2 tablespoons flour
 * ½ teaspoon salt
 * ½ teaspoon freshly ground black pepper
 * 2 cups milk
 * 1 cup mozzarella shredded
 * 1 cup cooked ham cubed
 * ¼ cup green onions sliced
 * 12 eggs beaten
 * ¼ cup fresh mushrooms sliced
 * 1½ cups soft bread crumbs

Directions
In Medium Saucepan Over Medium Heat Melt 2 Tablespoons butter ThenAdd flour, salt And pepper And Stir With a Whisk Until Well Blended.Gradually Add milk Then Cook Until Thickened And bubbly WhiskingConstantly. Once Thickened Remove From Heat And Stir in Cheese AndStir Until Melted Then Set Aside. in Large Skillet Melt 3Tablespoons butter Then Saut? Ham And onions Until Lightly Browned.Add eggs And Stir For 2 Minutes. Add Mushrooms And Cheese Sauce ThenMix Well. Pour Into Well Greased Baking Dish. in Medium SaucepanMelt Remaining butter And Toss With bread Crumbs. Sprinkle Over TopOf Casserole. Cover And Refrigerate or Overnight. Bake Uncovered at
 * 350 For 30 Minutes.