Cheesy Pizza Spaghetti Casserole

Pizza Spaghetti Casserole is the dinner you make when the whole family wants pizza but you need something that fills everyone up without ordering in. It is spaghetti baked with savory sausage, rich pizza sauce, and a whole lot of melted mozzarella.

This one comes out of the oven bubbling and golden, with crisp pepperoni on top if you want it. It tastes like pizza night in pasta form, and you only need one dish to pull it off.

Why This One Keeps Showing Up on the Table

The spaghetti stays tender, not mushy, because I cook it just shy of al dente before it hits the oven. The sauce clings to every strand, and the cheese gets that stretchy pull you expect from a good pizza. I love that it delivers the pepperoni and cheese moment without any doughy crust.

Cleanup is minimal, which matters on a busy weeknight. You can stretch it to feed a crowd, and leftovers reheat beautifully the next day. That last slice out of the fridge is dangerous in the best way.

Ingredients

• 1 lb spaghetti: regular or whole wheat, cooked just short of al dente
• 1 lb ground Italian sausage: mild or hot; you control the heat
• 1 small yellow onion, diced
• 3 cloves garlic, minced
• 2 cups pizza sauce: jarred or homemade, whichever you have
• 1 tsp Italian seasoning
• 1/2 tsp salt
• 1/4 tsp black pepper
• 2 cups shredded low-moisture mozzarella: the kind that melts into a molten blanket
• 1/2 cup grated Parmesan
• Optional: 1/4 cup sliced pepperoni, for topping

Variations / Substitutions

• Ground beef or turkey: use 1 lb of either. Ground turkey stays leaner, so add a tablespoon of olive oil as it browns.
• Meatless: skip the sausage and stir in 1 cup of sautéed mushrooms and diced bell peppers with the onion.
• Gluten-free spaghetti: cook 12 oz of your favorite gluten-free pasta until very firm, and it will hold up in the bake.
• Dairy-free: swap the cheeses for plant-based shreds that melt well and add a drizzle of olive oil to the sauce for richness.

If you like this mashup, you might also try my Baked Ziti with Sausage.

How to Make Pizza Spaghetti Casserole

Step 1: Cook the Pasta

Bring a large pot of salted water to a boil. Add the 1 lb spaghetti and cook about 8 minutes, just until it bends but still has a firm bite. Drain and rinse briefly with cool water to stop the cooking, then set it aside in the colander.

The noodles should look slightly undercooked. They will finish in the oven, so that chew protects you from mush.

Step 2: Brown the Sausage

Set a large skillet over medium-high heat and crumble in the 1 lb ground Italian sausage. Cook for 5 to 7 minutes, breaking it up with a wooden spoon, until no pink remains. Add the diced onion and cook 3 minutes more, just until the onion turns translucent. Stir in the minced garlic and let it go for 30 seconds, until it smells really fragrant.

At this point the meat should be deeply browned with little crispy bits on the bottom. That browning is where the savory depth comes from.

Step 3: Simmer the Sauce

Pour the 2 cups pizza sauce into the skillet, along with the 1 tsp Italian seasoning, 1/2 tsp salt, and 1/4 tsp black pepper. Stir everything together, bring it to a gentle simmer, and cook for 5 minutes. Turn the heat off and taste the sauce. Adjust the salt if it needs a pinch more.

The sauce will look thick and meaty, almost like a lazy Bolognese. You want it that way so the casserole does not turn watery.

Step 4: Layer and Bake

Preheat the oven to 375°F. Toss the drained spaghetti with the meat sauce right in the skillet or in a large bowl. Spread half of this mixture into a greased 9×13 baking dish. Sprinkle 1 cup of the shredded mozzarella and 1/4 cup of the Parmesan over the top. Add the remaining spaghetti mixture, then finish with the last 1 cup mozzarella and the remaining Parmesan. Bake uncovered for 25 minutes, until the edges are bubbling and the cheese is melted and beginning to spot golden.

The layers mean every bite has cheese pulling through. Do not cover the dish, or the top will steam instead of brown.

Step 5: Broil and Serve

Remove the casserole and scatter the optional pepperoni slices over the top. Set the oven to broil and slide the dish back in for 2 to 3 minutes, watching closely, until the pepperoni curls and crisps and the cheese blisters. Take the casserole out and let it sit for 5 minutes so the layers set before you cut into it. Slice into squares and serve hot, spooning any saucy bits from the bottom over each portion.

That final broil gives you the same crackling top you get from a pizzeria oven. The wait is tough, but the slices hold together better after a short rest.

Tips for the Best Casserole

• Cook the pasta firm.: It will absorb moisture in the oven, so stopping early keeps it from getting soggy.
• Use low-moisture mozzarella.: Fresh mozzarella releases too much water and can leave the casserole soupy.
• Let it rest before slicing.: Five minutes off the heat gives the cheese a moment to set so the squares stay neat on the plate.
• Customize the toppings.: Sliced black olives, mushrooms, or green peppers go well scattered over the top before baking.

Storing Leftovers

• Refrigerate: Cool the casserole completely, then cover tightly and refrigerate for up to 4 days.
• Reheating: Warm individual portions in the microwave for 1 to 2 minutes, or cover the whole dish with foil and reheat at 350°F for 15 to 20 minutes until hot throughout.

What To Serve With Pizza Spaghetti Casserole

This is a rich, filling dish, so I keep the sides simple. A crisp green salad with a sharp vinaigrette cuts through the cheese and meat. For something more comforting, garlic bread baked alongside is never a bad move. Roasted broccoli tossed with lemon and red pepper flakes adds a bright, spicy note that balances the plate.

Frequently Asked Questions

Can I use a different pasta shape?

Yes. Short shapes like penne, rigatoni, or ziti work well and hold the sauce just as nicely.

How do I make this ahead of time?

Assemble the casserole without baking, cover it, and refrigerate for up to 24 hours. Add 5 to 10 minutes to the bake time since it will go into the oven cold.

Can I freeze leftovers?

Yes. Portion cooled casserole into freezer-safe containers and freeze for up to 3 months. Thaw overnight in the fridge before reheating.

What if I do not have pizza sauce?

You can use plain marinara or tomato sauce and add a teaspoon of sugar and a pinch more Italian seasoning to mimic that pizza flavor.

Pizza Spaghetti Casserole Recipe

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Prep Time 15 minutes mins

Cook Time 35 minutes mins

Total Time 50 minutes mins

Servings: 8 servings

Calories: 510

Ingredients Method Notes

Ingredients

  

• 1 lb spaghetti
• 1 lb ground Italian sausage
• 1 small yellow onion, diced
• 3 cloves garlic, minced
• 2 cups pizza sauce
• 1 tsp Italian seasoning
• 1/2 tsp salt
• 1/4 tsp black pepper
• 2 cups shredded low-moisture mozzarella
• 1/2 cup grated Parmesan
• Optional: 1/4 cup sliced pepperoni, for topping

Method

 

1. Cook spaghetti in salted boiling water about 8 minutes until just firm, then drain and rinse briefly with cool water.
2. In a large skillet over medium-high heat, brown the sausage with onion and garlic, breaking up the meat, 5 to 7 minutes.
3. Stir in pizza sauce, Italian seasoning, salt, and pepper. Simmer 5 minutes until thick.
4. Preheat oven to 375°F. Toss spaghetti with the meat sauce and layer half in a greased 9×13 dish with 1 cup mozzarella and 1/4 cup Parmesan. Top with remaining spaghetti mixture and cheeses. Bake uncovered 25 minutes.
5. If using pepperoni, scatter over the top and broil 2 to 3 minutes until crisp. Let rest 5 minutes, then slice and serve.

Notes

Let the casserole rest a few minutes after baking so it cuts into neat squares. If you skip the broil, the cheese will still be melted and golden from the bake, but the pepperoni will soften rather than crisp.