You are here: Home » Recipes » Spinach Beef Casserole Spinach Beef Casserole Recipe by Relish ContributorKitchen Tested Yield 6 servings This easy casserole can be made ahead and cooked later, or frozen after cooking. PrintEmail Ingredients 1 1/4 pounds ground sirloin1 medium onion, chopped1 (8-ounce) can mushroom stems and pieces, drained1 tablespoon minced garlic1 teaspoon dried oregano2 (10-ounce) packages frozen chopped spinach, thawed and squeezed dry1 (10 3/4-ounce) can reduced-fat cream of celery soup1/2 cup rice1/2 cup skim milk Salt and pepper to taste1 cup shredded reduced-fat mozzarella cheese Instructions Preheat oven to 350F. In a large skillet, cook meat, onion, mushrooms, garlic and oregano over medium-high heat until meat is done, 5 to 8 minutes. Drain any excess grease. Spoon into a 2-quart casserole dish coated with nonstick cooking spray. Mix in spinach, cream of celery soup, rice, milk, and salt and pepper. Bake 35 to 45 minutes. Sprinkle mozzarella on top and continue baking 5 minutes more, or until cheese is melted.