Spinach Beef Bake - cooking recipe

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

Preparation

In a skillet over medium heat cook beef and onion until meat is no longer.
pink; drain.
In a bowl, beat eggs.
Add spinach and mushrooms; mix well.
Stir in cheeses, garlic powder, salt /pepper and beef mixture; mix well.
Drizzle with buter.
Bake uncovered at 375 for 25-30 minutes.