Asparagus Bella Strata

Wash asparagus and break off woody ends. Cut asparagus into 1-inch pieces. Thinly slice mushrooms and set both aside. Spray an 8"x8"x2" baking pan with cooking spray. Split muffins and place cut sides up in bottom of pan. Sprinkle with asparagus and mushrooms. In a small bowl, beat eggs with milk and mustard until well blended. Season as desired with salt and black pepper. Pour egg mixture over muffins and vegetables. Sprinkle cheese on top and cover with foil; refrigerate overnight. Preheat oven to 350 degrees. Remove foil and bake for 45-50 minutes or until knife inserted into center comes out clean. Allow to sit at room temperature for 10 minutes before serving.