Spray muffin tin cups with cooking spray.
Cook pasta shells according to package directions for 12 minutes. Do NOT overcook. Drain and rinse.
Turn shells inside out and place 1 shell in each muffin tin cup.
Preheat oven to 350°F.
Mix together spinach, ricotta, ham, 1 1/2 cups cheese, green onion, egg, crushed red pepper, black pepper, and garlic salt.
Fill pasta shells with spinach mixture. Pour alfredo sauce onto shells.
Spray a piece of foil with cooking spray, and cover the pan, spray side down. Bake for 30 minutes.
Remove foil, and sprinkle with remaining cheese. Bake an additional 10 minutes or until cheese is melted.
Drizzle with any additional heated alfredo sauce when serving.