Spinach Beef Bake

Ingredients

• 1 1/2 lbs ground beef
• 1/2 cup finely chopped onion (I used a whole onion)
• 2 eggs
• 10 ounces frozen chopped spinach, thawed and squeezed dry (I sauteed mine a bit to soften and season it)
• 4 ounces mushroom stems and pieces (I added some fresh sauteed mushrooms also)
• 4 ounces crumbled feta (I used almost the double this amount of cheese-monterey jack) or 4 ounces shredded monterey jack cheese (I used almost the double this amount of cheese-monterey jack)
• 1/4 cup parmesan cheese
• 1 1/2 teaspoons garlic powder (I added some fresh minced garlic also)
• salt and pepper
• 1 -2 tablespoon butter or 1 -2 tablespoon margarine, softened