This super simple leftover pasta casserole is an easy way transform leftover spaghetti sauce and pasta into a hot and gooey baked meal with a quick bread crumb and parmesan topping. It’s an easy and comforting weeknight dinner that’s oven-ready and hot in just a few simple steps…

This is one of my favorite things to throw together in a flash when I want to give my leftovers a quick makeover and feed hungry mouths in a hurry! Let’s take a quick look at how to throw this together…

Leftover Pasta Casserole with quick Parmesan Topping

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1. Start by smearing sauce on the bottom of the baking dish

Ladle some leftover spaghetti sauce into the casserole dish. In my case, I had a leftover spaghetti meat sauce that I added in cold, right outta the fridge. You could easily use your favorite marinara sauce in its place if you aren’t working with leftover sauce.

Use the bottom of your ladle to evenly spread enough leftover spaghetti sauce around to create a quick first layer.

Related: Simple Ground Turkey Bolognese

2. Add Green Vegetables to the leftover pasta casserole

Next, add a green vegetable of your choice, if desired. I’ll usually toss in half-cooked broccoli florets or any tender and quick-cooking green veggie.

Green Vegetable Ideas & Substitutions for your Leftover pasta casserole

• Feel free to add any green vegetables you have available.
• You could add thin sliced bell peppers or some asparagus spears.
• You could use fresh rough chopped spinach or a frozen spinach (let frozen spinach come to a thaw, strain and press excess water out and then add).
• If needed, steam/cook your thicker/heartier vegetables about halfway through and then toss them in. They will cook the rest of the way as they heat in the casserole.

3. Layer On Some Pasta to create a leftover pasta casserole

Grab your leftover (cooked) short pasta and sprinkle that over the top of the sauce layer. In my case, I did a mix of pipe rigate pasta and tricolor rotini for a little fun texture.

4. Spread the rest of The leftover spaghetti Meat sauce over the pasta layer

Spread the last of your leftover spaghetti sauce over the pasta to coat it as evenly as possible. I kept adding sauce to this layer until the pasta was nicely covered by the red sauce.

If you were wondering what to do with leftover spaghetti meat sauce and leftover pasta, here’s your answer! We bake ’em both up into a quick casserole just like this one…

4. Sprinkle A Melty Cheese Over your leftover Pasta

Finish off by sprinkling on some cheese. I chose to use shredded mozzarella, but you can use your favorite cheese!

Choose a cheese that melts easily

You can add any type of cheese that melts nicely in the oven. Mozzarella, fontina, or even provolone would do very nicely! Spread these right over the top.

5. Spray Your Foil Sheet with A little non-stick Cooking Spray

Before you cover your casserole: spray your foil with a quick coating of pam or non-stick spray. This will stop the cheese topping from sticking to the foil.

6. Heat The Leftover Pasta Casserole In The Oven

Cover the casserole with a tight-fitting sheet of foil so everything can heat nicely and bubble up in the oven.

Bake the pasta casserole covered in a 375 degree F oven for 20 to 25 minutes to heat the inside through.

While the casserole heats in the oven, mix a quick parmesan cheese and bread crumb topping. Combine Italian-style bread crumbs with grated Parmigiano Reggiano cheese in a small bowl and stir together. Set aside.

When 20 to 25 minutes of cook time is up, remove the sheet of foil and continue cooking for another 10 minutes uncovered.

Cook only until shredded mozzarella cheese is just evenly melted (but not browned) and the inside juices are bubbling.

5. Sprinkle on the Parmesan and Bread crumb topping

Sprinkle the parmesan and bread crumb mixture over the melted mozzarella. This will add a delicious little crumb topping that takes that melty cheese layer right over the top! It’s just a little extra finishing touch that browns nicely at the end.

Brown The Parmesan Bread Crumb Topping on the Leftover Pasta Casserole

Turn the broiler on LOW and heat the casserole until the toppings are just golden brown. About 3 to 5 minutes.

*** Do not leave the stove area at this point as the toppings will go from golden to burned in just minutes while the broiler is in use. Stay right nearby and remove promptly between 3 to 5 minutes. If you’re oven is fast, check the coloring on the toppings even sooner. This process happens quite quickly.

Serve Hot and Dig In!

Serve with a quick salad and some garlic bread and dig in! I hope this easy leftover spaghetti casserole gives you quick and easy inspiration for a baked weeknight bite! For a tender and juicy vegetable-filled casserole, check out this easy baked ratatouille!

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