In a large skillet, cook the sausage over medium heat until no longer pink; drain. Add the eggs, milk, bread, cheese, bacon and mustard. Transfer to a greased, shallow, 3-qt. baking dish. Cover and refrigerate for 8 hours or overnight. Remove from the fridge 30 minutes before baking. Cover and bake at 350 for 60-65 minutes or until a knife inserted near the centere comes out clean.