4 tbsp. (1/2 stick) butter, melted and divided
1 lb. med. size whole mushrooms
1 tsp. salt
1/4 c. finely chopped onion
2 (10 oz.) pkgs. frozen spinach, thawed and drained
1 c. (4 oz.) shredded Cheddar cheese, divided
Garlic to taste

Preheat oven to 350 degrees. Place 2 tablespoons of butter in a large skillet over medium heat, heat. Add the mushrooms and cook until browned, browning the cap sides first. Stir the salt, onion and remaining 2 tablespoons butter into the spinach. Line a 10-inch casserole with the spinach mixture. Sprinkle 1/2 cup of the cheese over the spinach.

Arrange the browned mushrooms over the cheese; season with the garlic salt and top with the remaining 1/2 cup cheese. Bake for 20 minutes or until the cheese is melted and browned. Serve hot.