Place spinach in a wire strainer and press out all water; set aside.

In a non-stick skillet over medium heat, brown ground beef. Add onions and mushrooms; cook until onions are translucent. Remove from heat and stir in spinach, sour cream, salt, nutmeg, Italian seasoning and half of Cheddar cheese. Pour into a 2 qt. baking dish that has been sprayed with non-stick cooking spray. Sprinkle remaining cheese on top.

Bake, uncovered, at 350 degrees for 20 minutes.

Nutrition Information per serving:
289 Calories; 4g Fat (20.7% calories from fat); 18g Protein; 12g Carbohydrate; 4g Dietary Fiber; 29mg Cholesterol; 593mg Sodium.  Exchanges: 0 Grain(Starch); 1 Lean Meat; 1 1/2 Vegetable; 0 Fat; 1/2 Other Carbohydrates.