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This baked spaghetti casserole is creamy, comforting, and checks off all the boxes for flavor! The white cream sauce coats every strand of spaghetti, along with mushrooms, and vegetables. With simple pantry ingredients, it is easier than ever to make this casserole.

a wooden spoon scooping into the spaghetti casserole
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Ingredients for Baked Spaghetti Casserole

  • Spaghetti pasta – uncooked, dried spaghetti pasta. You could use fettuccine or angel hair, but you’d have to adjust cooking time. Angel hair cooks quite a lot faster!
  • Butter – unsalted or salted. Just be aware if you use salted butter to adjust your seasonings.
  • Mushrooms – lots of mushrooms are used in this casserole for that extra hearty bulk in this dish.
  • Onion – yellow or white, whichever you prefer!
  • Bell peppers – both green and red bell peppers are used.
  • Celery
  • Cream of mushroom – I know, I know, but it’s so good! If you’d rather make your own, here is a great recipe.
  • Milk – whole milk to make the sauce extra rich.
  • Cheese – you’ll be using three kinds of shredded cheese for this recipe: extra sharp cheddar, Monterey Jack, and Colby Jack!

How to Make Spaghetti Casserole Step by Step

For full, detailed recipe instructions, please scroll down to the recipe card.

  • Set oven and bring a pot of water to a boil. Preheat oven to 350 degrees Fahrenheit and bring a large pot of water to a boil. Add the pasta to the water and cook halfway (or al dente) as it will finish cooking in the oven.
  • Cook the vegetables. In the meantime, cook the vegetables in butter on the stovetop in a skillet.
  • Stir everything to combine and bake. Add the milk and cream of mushroom into a large bowl and whisk together to combine. Add the cooked vegetables, spaghetti, and cheeses and stir to combine all together. Pour into a large casserole dish and bake for 30-35 minutes, or until pasta is cooked through and sauce is bubbling.
inside of spaghetti casserole next to grey linen towel

Spaghetti Casserole Variations

  • Use different cheeses. Using a different cheese like ricotta cheese or cottage cheese would give this an extra creamy feel. Additionally, if you don’t have the shredded cheeses listed, you may use a similar alternative. Try to make sure you are shredding it yourself from a block instead of getting it pre-shredded. It yields a much creamier and less gritty sauce.
  • Add a protein. If you desire to further bulk up this spaghetti casserole, adding shredded chicken or diced chicken would be a nice, light addition. Smoked sausage would give this a different, but tasty, flavor profile.
  • Spice it up. Add more cayenne pepper or red pepper flakes to amp up the spice level.


Can I add protein to this casserole and when would I add it in?

Yes! If you are using shredded chicken, it is pre-cooked so you can just stir it in with everything else in the bowl prior to adding to the casserole dish. If you are using raw chicken, dice it into small cubes and stir it in with everything else in the bowl then add it to the casserole dish. With the casserole baking at 30-35 minutes, it will cook the chicken through if diced small enough.

Shrimp is another good candidate for this and so is ground beef or ground turkey. If you’re using ground beef or ground turkey, I would cook it in the skillet and break it into smaller pieces prior to adding to the pasta dish.

Can I use whole wheat or chickpea pasta in this?

You can, it just might take a little longer to cook.

What kind of pasta shapes can I use?

Linguine, fettuccini, or any long pasta shapes. If you want to use cut pasta shapes, penne or rigatoni would work but you may have to adjust cook time.

spaghetti casserole in a large bowl with metal utensils

Storage Instructions

Allow pasta to come to room temperature then store in an airtight container in the refrigerator for up to 4 days. To reheat, pop in the microwave or in a pot on the stovetop. Be aware that the sauce will be thick due to the temperature change so you’ll need to add a little bit of liquid to loosen it all up again.

Serving Suggestions

Serving spaghetti casserole with a side of Garlic Knots would be my choice! A simple side salad for that balance!

More Casserole Recipes

4.43 from 7 votes

Spaghetti Casserole

This spaghetti casserole is creamy, comforting, and checks off all the boxes for flavor! With simple pantry ingredients, it is easier than ever to make this casserole.
Prep Time: 20 minutes
Cook Time: 35 minutes
Total Time: 55 minutes
Servings: 6



  • 8 ounces (227 g) dried spaghetti pasta
  • 1 tablespoon (14 g) unsalted butter
  • 2 cups (192 g) sliced mushrooms
  • 1 medium onion, diced
  • ½ green bell pepper, diced
  • ½ red bell pepper, diced
  • 3 stalks of celery, diced
  • 21.5 ounces (610 g) canned cream of mushroom soup
  • 1 cup (237 ml) whole milk
  • ¼ teaspoon cayenne pepper, or more depending on how spicy you like yours
  • 1 cup (113 g) freshly shredded extra sharp cheddar cheese
  • cup (75 g) shredded Monterey Jack cheese
  • cup (44 g) shredded Colby Jack cheese
  • Salt and pepper, to taste
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  • Preheat oven to 350 °F (177 °C) and lightly grease a 9×13 inch casserole dish.
  • In a large pot, boil and season water with salt. Cook pasta until al dente. Drain and set aside.
  • In a large skillet, melt the butter over medium-high heat and add in all your veggies (mushrooms, onion, bell peppers, and celery). Sauté until they are soft and translucent, about 7 minutes.
    mushrooms, celery, onions, and bell peppers in a large skillet with a wooden spoon
  • In a separate large bowl, whisk together milk, cream of mushroom, and cayenne pepper and whisk until smooth.
  • Add the cooked vegetables and extra sharp cheddar cheese into the bowl then stir until well-combined. Add the pasta to the bowl and toss until everything is mixed through thoroughly and coated with the milk mixture.
    vegetable mixture with milk and cream of mushroom and shredded cheese in a skillet with a wooden spoon
  • Pour all the contents of the bowl into the prepared casserole dish then sprinkle Monterey Jack and Colby Jack cheese all over the top in an even layer. Season with salt and pepper.
    freshly shredded cheese on top of spaghetti mixture in a casserole dish
  • Cover and bake in the oven for about 30-35 minutes or until cheese is melted and casserole is bubbling. Remove the cover for the remaining 10 minutes of baking to get the cheese browned.
  • Remove from oven and allow to sit for 15 minutes before serving.


Serving: 1Serving, Calories: 329kcal, Carbohydrates: 27g, Protein: 14g, Fat: 19g, Fiber: 3g, Sugar: 4g

This website provides approximate nutrition information for convenience and as a courtesy only. Nutrition information can vary for a variety of reasons. For the most precise nutritional data use your preferred nutrition calculator based on the actual ingredients you used in the recipe.

The default measuring system for this website is US Customary. Unit conversions are provided for convenience and as a courtesy only. While we strive to provide accurate unit conversions, please be aware that there may be some discrepancies.

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Photography by Jess Reilly

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Recipe Rating


  1. I’m looking forward to trying this, as well as some of your other recipes! I never use cream-of-whatever soups anymore since I found this excellent substitute:

    Home-made substitute for 1 can of condensed Cream of Mushroom Soup:

    2 Tbsp. butter
    2 Tbsp. canola oil
    1/4 cup all purpose flour
    1/4 tsp. salt
    2 fresh mushrooms, finely chopped
    10 ounces milk

    Heat butter and oil then add flour and salt, stirring to make a roux. Add mushrooms and cook about a minute, just to soften. Add milk and stir until thickened.

    To make cream of chicken soup, simply omit mushrooms, add 1 tsp. chicken bouillon, and substitute half the milk with chicken broth or stock.

    To make cream of celery soup, substitute celery for the mushrooms.

    1. Brilliant idea…thanks for the tip..That shall be my way to go now…
      My problem is I live on my own since my husband passed away so trying all the time to halve recipes or opening things and not knowing what to do with the rest..this is great as I can make just enough for one dish..Thank you…

  2. I made this for my husband and he said this dish is a keeper! I changed things a little I used whole wheat thin spaghetti pasta and I added chicken. I loved it. Thanks for sharing your recipe. Like you it’s hard to make dinner for two! We sometimes have leftovers…if we don’t serve ourselves big portions.

  3. I learned years ago that learning to cook from watching my Mother that I would never learn to cook for two. I did learn, however, to freeze some of the meal for emergencies. Its wonderful to drop the freezer bags in boiling hot water and supper is ready. Yea….

    1. thanks! it is really good :) and I had a ton of leftovers! the different pasta shapes is a good idea :) enjoy!