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Easy Leftover Spaghetti Casserole Recipe for a Cozy Family Dinner

Easy Leftover Spaghetti Casserole Recipe

Chilled leftover spaghetti is combined with a creamy egg-and-cheese mixture, topped with marinara and mozzarella, and baked into a comforting 6-serving casserole.
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Prep Time 10 minutes
Cook Time 25 minutes
Total Time 40 minutes
Servings: 6 servings
Ingredients Method Notes

Ingredients
  

Main Ingredients
  • 4 cups Cooked leftover spaghetti, chilled
  • 2 cups Prepared marinara or spaghetti sauce, divided
Cheese and Egg Mixture
  • 2 Large eggs
  • 1/2 cup Grated Parmesan cheese
  • 1 cup Ricotta cheese or small-curd cottage cheese
Cheese Topping
  • 1 1/2 cups Shredded mozzarella cheese, divided
Seasonings
  • 1/2 teaspoon Italian seasoning
  • 1/2 teaspoon Garlic powder
  • 1/4 teaspoon Salt
  • 1/4 teaspoon Black pepper
Garnish and Pan Preparation
  • 1 tablespoon Chopped fresh parsley, optional
  • 1 teaspoon Nonstick cooking spray or olive oil

Method
 

Step-by-Step
  1. Heat the oven to 350°F (175°C) and lightly grease a 9-by-13-inch baking dish with nonstick cooking spray or 1 teaspoon olive oil.
  2. In a large bowl, whisk together the eggs, Parmesan, ricotta or cottage cheese, Italian seasoning, garlic powder, salt, and black pepper until the mixture is evenly combined.
  3. Add the chilled cooked spaghetti and 1 cup of the prepared sauce to the bowl. Toss thoroughly so the strands separate and become evenly coated with the egg-and-cheese mixture.
  4. Spread the spaghetti mixture evenly in the prepared baking dish. Spoon the remaining 1 cup sauce across the surface, keeping the pasta covered so it stays moist during baking.
  5. Sprinkle the 1 1/2 cups shredded mozzarella evenly over the sauce. Cover the dish loosely with foil so the cheese does not stick and the casserole does not dry out.
  6. Bake covered for 20 minutes, then carefully remove the foil. Continue baking for another 5 to 10 minutes, until the mozzarella is melted and lightly browned and the center is hot throughout.
  7. Let the casserole rest for 5 to 10 minutes before cutting. Garnish with chopped fresh parsley if desired, then serve warm.

Notes

Use leftover spaghetti that was refrigerated promptly and kept for no more than 3 to 4 days. If the pasta is dry or clumped, toss it with a few tablespoons of water or extra sauce before mixing. A casserole assembled while cold may need 30 to 35 minutes at 350°F to reheat fully.