Spinach-Stuffed Mushrooms... Spinach-Stuffed Mushrooms Ingredients PAM® Olive Oil No-Stick Cooking Spray 2 pkgs (16 oz each) large mushrooms 1 small onion, chopped 1 pkg (10 oz each) frozen chopped spinach, thawed, squeezed dry 1/4 cup dry unseasoned bread crumbs 1/4 cup grated Parmesan cheese (1/4 cup = 1 oz) 1 tablespoon chopped pimiento 1/2 teaspoon