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This Chicken Spaghetti Casserole is creamy, cheesy, and filled with tender chicken, spaghetti, Rotel tomatoes, and thinly sliced peppers and onions. Everything gets tossed in a creamy sauce, topped with sharp cheddar, and a great way to use leftover or rotisserie chicken.
Why I Love This Casserole
This is exactly the kind of casserole I want when I am craving something creamy and cheesy but still easy enough for a weeknight. I wanted the sauce to be really smooth and creamy without using Velveeta, so I use sharp cheddar along with sour cream, cream cheese, and condensed soups. The ranch seasoning gives it a little extra flavor without making the whole thing taste like ranch.
I also slice the bell pepper and onion really thin so you don’t get big chunks of vegetables mixed in with the spaghetti. They soften up quickly and blend right in with the noodles. My other little trick is blending the sauce before adding it to the skillet. You definitely don’t have to do this, but I love how smooth it makes the sauce and it gets the cream cheese completely mixed in.
And of course there is Rotel! The tomatoes and green chilies break up all that creaminess and give the casserole just the right amount of flavor without making it too spicy.
🩷 Erica
Key Ingredients
- Spaghetti – Regular spaghetti noodles work best for that classic chicken spaghetti texture. Cook them just until al dente so they don’t get too soft in the oven.
- Chicken – You can use any cooked, shredded chicken. I usually grab a rotisserie chicken when I want to make this extra easy.
- Bell pepper and onion – I slice these REALLY thin so they soften quickly and blend right in with the noodles.
- Creamy sauce – Cream of mushroom soup, cream of chicken soup, sour cream, cream cheese, and chicken broth make the sauce extra creamy without needing Velveeta. If you don’t love the condensed soups in a can and would rather make them from scratch, we have homemade recipes for both cream of chicken soup and cream of mushroom soup.
- Rotel tomatoes – Tomatoes with green chilies add just enough flavor and a tiny bit of heat to balance the creamy sauce.
- Sharp cheddar cheese – I like sharp cheddar here because you get a lot of cheesy flavor without having to add a ton of cheese. I always prefer shredding it from a block because it melts better.
- Ranch seasoning – Just a tablespoon gives the sauce a little extra zip. Don’t worry, it doesn’t make the casserole taste like ranch.
- Avocado oil – I use this to sauté the vegetables, but vegetable oil works just as well.
- Salt and pepper – Add these to taste. Remember that the condensed soups, broth, ranch seasoning, and cheese already contain salt, so I like to taste before adding too much.
Substitutions and Variations
Use rotisserie chicken. This is probably my favorite shortcut. Pull the meat from a rotisserie chicken and shred or chop it into bite-sized pieces. Leftover baked or grilled chicken works great too.
Make it less spicy. Regular Rotel isn’t extremely hot, but if you are serving someone who doesn’t like any heat, use mild Rotel. You can also use plain diced tomatoes and a small amount of diced green chilies.
Make it spicier. Use hot Rotel or add some diced jalapeños, cayenne pepper, or crushed red pepper flakes to the sauce.
Skip the mushrooms. If cream of mushroom soup isn’t your thing, replace it with another can of cream of chicken soup.
Try a different cheese. I love sharp cheddar because it adds the most flavor, but Monterey Jack, Colby Jack, or a combination of cheeses will work too.
Use a different pasta. Spaghetti is what makes this chicken spaghetti, but linguine, fettuccine, or another sturdy pasta can work in a pinch. Just be sure not to overcook it before it goes into the casserole.
Add more vegetables. Mushrooms, spinach, or another color of bell pepper can easily be added. Sauté vegetables first so they don’t release a bunch of extra liquid into the casserole while it bakes.
How to Make Chicken Spaghetti Casserole
- Heat the oven to 350 degrees and coat a 9×13-inch baking dish with cooking spray. Cook the spaghetti just until al dente, then drain and set aside.
- Heat the oil in a large skillet or Dutch oven over medium heat. Add the bell peppers and onion and cook for 6 to 7 minutes, until they begin to soften. I like to slice them extra thin so they cook quickly and blend right in with the spaghetti.
- Blend the cream of mushroom soup, cream of chicken soup, sour cream, chicken broth, cream cheese, ranch seasoning, salt, and pepper until smooth. You can also whisk everything together in a bowl if you don’t want to use a blender.
- Stir the shredded chicken and Rotel into the cooked peppers and onions, then pour in the sauce. Add 1 cup of cheddar cheese and stir until everything is creamy and combined.
- Toss the cooked noodles with the chicken and sauce using tongs until everything is evenly coated. Transfer the mixture to the prepared baking dish and sprinkle the remaining cheese over the top.
- Bake for 25 to 30 minutes, until the casserole is hot and bubbly and the cheese is melted. Let it rest for about 5 minutes before serving.
Expert Recipe Tips
Don’t overcook the spaghetti. This is probably my biggest tip. The noodles are going back into the oven for another 25 to 30 minutes, so you want them just barely al dente when you drain them. Overcooked noodles can turn soft and mushy in the casserole.
Slice the vegetables extra thin. I like the flavor of the bell pepper and onion, but I don’t want big pieces of them competing with the spaghetti. Slice them as thin as you can. I sometimes use a vegetable peeler to get really thin strips.
Blending the sauce is optional, but I love it. You can absolutely whisk the sauce ingredients together in a bowl, but giving everything a quick spin in the blender makes the sauce super smooth and gets rid of any little pieces of cream cheese.
Have picky eaters? Blend the veggies in with the sauce. If you want the casserole completely creamy with no noticeable pieces of pepper or onion, sauté the vegetables first, then blend them right in with the sauce ingredients. You still get all that flavor, but the veggies basically disappear into the sauce.
Lightly drain the Rotel. I don’t press out every drop of liquid because I want a little of that tomato and green chile flavor in the sauce. Just drain off the obvious excess so the casserole doesn’t get watery.
Shred your own cheese if you can. Pre-shredded cheese is convenient, but freshly shredded cheddar melts into the sauce more smoothly. Sharp cheddar also gives you more cheese flavor.
Use tongs to combine everything. Once the spaghetti goes into the skillet, tongs make it MUCH easier to get the noodles evenly coated without breaking them into little pieces.
Let it rest before serving. Give the casserole about 5 minutes after it comes out of the oven. The sauce thickens slightly as it sits, which makes it much easier to scoop onto plates.
Frequently Asked Questions
Yes. Assemble the casserole completely, but don’t bake it. Cover it tightly and keep it in the refrigerator for up to 24 hours. When you are ready to eat, bake it as directed. It may need a few extra minutes in the oven since everything is starting out cold.
No. If you don’t like mushrooms, use two cans of cream of chicken soup instead. You could also use cream of celery for one of the cans if you like that flavor.
The most common culprits are overcooking the spaghetti before baking, draining too much liquid from the Rotel, or leaving the casserole in the oven too long. Cook your pasta just until al dente and pull the casserole from the oven as soon as it is hot and bubbly.
I would call this casserole mild. Rotel gives it a little zip, but all of the creamy ingredients and cheese mellow it out quite a bit. If you are sensitive to spice, use mild Rotel. If you like more heat, use hot Rotel or add jalapeños.
If you don’t want to used the soup from the can, you can use our homemade versions of both the cream of mushroom soup and cream of chicken soup!
Make Ahead and Storage
Make ahead: You can assemble the Chicken Spaghetti Casserole up to 24 hours in advance. Prepare the casserole through the step where it is transferred to the baking dish and topped with cheese, then cover tightly and refrigerate without baking. When you’re ready to serve it, bake as directed. Since it will be starting cold, you may need to add a few extra minutes to the baking time.
Storing leftovers: Cover the baking dish tightly or transfer leftovers to an airtight container and refrigerate for 3 to 4 days.
Freezing: This casserole can also be frozen. Let it cool completely, then wrap individual portions or the entire casserole tightly and freeze. For the best texture, thaw it overnight in the refrigerator before reheating. Keep in mind that creamy sauces and pasta can have a slightly different texture after freezing.
Reheating: Reheat individual servings in the microwave until heated through. For a larger portion, cover with foil and warm in a 350-degree oven until hot. If the spaghetti seems a little dry, add a small splash of chicken broth before reheating.
What to Serve with Chicken Spaghetti
This casserole is pretty rich and filling on its own, so I like to keep the sides simple. Oven Roasted Green Beans are an easy way to add a vegetable, or make a simple Caesar salad with our homemade Caesar Dressing. If you want some bread for scooping up that creamy sauce, these Easy Garlic Breadsticks are SO good on the side.
More Easy Chicken Casserole Recipes
Have you tried this Chicken Spaghetti Casserole? I’d love to hear what you think! Drop a comment and a rating belowand let me know how your family liked it. And don’t forget to take a pic and tag us on Instagram @favoritefamilyrecipes! 📸🍝
Chicken Spaghetti Casserole
Ingredients
- 16 ounces spaghetti noodles
- 2 tablespoons avocado oil, or vegetable oil
- 1 red bell pepper, sliced thin
- 1 small yellow onion, sliced thin
- 1 (10.5 ounce) can condensed cream of mushroom soup
- 1 (10.5 ounce) can condensed cream of chicken soup
- 1/2 cup chicken broth
- 8 ounces sour cream
- 4 ounces softened cream cheese
- 2 ½ cups sharp cheddar cheese, divided
- 1 tablespoon ranch seasoning
- salt and pepper, to taste
- 1 (10 ounce) can Rotel tomatoes with green chilies, lightly drained
- 3 cups chicken, cooked and shredded (rotisserie chicken works great)
Instructions
- Preheat oven to 350 degrees. Spray a 9×13-inch baking dish with cooking spray and set aside.Cook the spaghetti according to the package directions until just al dente (do not overcook). Drain and set aside.
- While the spaghetti is cooking, heat the oil in a large high-walled skillet or Dutch oven over medium heat. Add the bell peppers and onion and sauté for 6-7 minutes, or until they start to soften. I like to slice the peppers and onions really thin with a vegetable peeler so they cook quickly and blend right in with the spaghetti.
- In a blender, combine the cream of mushroom soup, cream of chicken soup, sour cream, chicken broth, cream cheese, ranch seasoning, and salt and pepper. Blend until smooth. This step is totally optional, but I like how smooth and creamy it makes the sauce. You can also just whisk everything together in a bowl.
- Add the shredded chicken and Rotel tomatoes to the skillet with the peppers and onions. Stir to combine, then pour in the sauce. Add 1 cup of the cheddar cheese and stir until everything is creamy and well combined.
- Add the cooked spaghetti to the skillet. Use tongs to toss the noodles with the chicken and sauce until everything is evenly coated.
- Pour the spaghetti mixture into the prepared baking dish and spread it out evenly. Sprinkle the remaining 1 ½ cups of cheddar cheese over the top.
- Bake for 25-30 minutes, or until the casserole is heated through and the cheese is melted and bubbly. Let it sit for about 5 minutes before serving.
Notes
- Cook the spaghetti just until al dente so it doesn’t become soft or mushy while the casserole bakes.
- Slice the bell pepper and onion very thin so they soften quickly and blend into the spaghetti.
- Lightly drain the Rotel, removing excess liquid but leaving a little behind for flavor and moisture.
- Blending the sauce is optional, but it gives it an extra smooth, creamy texture. You can also whisk everything together.
- For the best melt, shred the cheddar from a block instead of using pre-shredded cheese.
- Use tongs to toss the spaghetti with the sauce so the noodles stay intact and get evenly coated.
- Let the casserole rest for about 5 minutes after baking so the sauce can thicken slightly before serving.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
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