Brown and drain sausage. Slice and sautee mushrooms. Mix with sausage, green onions, pimento, salt, pepper, dry mustard. In a separate bowl, mix eggs, milk, and Worchestershire Grease 9 x 13" pan. Cover bottom of pan with bread, then spoon sausage mix over. Top with remaining bread. Pour egg and milk mix over. (Can be assembled to this point and refrigerated overnight.)
Bake at 350 for 1 hour and 10 minutes. Sprinkle with grated cheddar and put back in the oven til melted.