2 cans (8 ounces each) mushroom stems and pieces, drained
2 large eggs, lightly beaten
3 cups shredded part-skim mozzarella cheese
1 unbaked deep-dish pastry shell (9 inches)
1 cup shredded cheddar cheese
In a large skillet, cook sausage and onion over medium heat until meat is no longer pink; drain. Stir in spinach and mushrooms. Combine eggs and mozzarella cheese; fold into sausage mixture. Spoon into pastry shell.
Cover and bake at 400° for 30 minutes. Uncover; sprinkle with cheddar cheese. Bake 10-15 minutes longer or a knife inserted in the center comes out clean. Freeze option: Securely wrap and freeze cooled quiche in plastic and foil. To use, partially thaw in refrigerator overnight. Remove from refrigerator 30 minutes before baking. Preheat oven to 350°. Unwrap quiche; reheat in oven until heated through and a thermometer inserted in center reads 165°.