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Some recipes are so good they stand the test of time. Chicken Spaghetti Casserole is one of those classic southern comfort foods that has earned a permanent place at family dinners. Grandma may have made it best, but we’re giving this classic a 21st-century update. But don’t worry- this version gives the beloved southern casserole a fresh update without losing what made everyone love it in the first place.
This cheesy chicken spaghetti starts with a shortcut that will make weeknight cooking easier: rotisserie chicken. And unlike the old-school versions that rely heavily on canned ingredients, this recipe builds so much more flavor and texture from the fresh vegetables and simple pantry staples you likely have on hand.
Sautéed peppers, onions, olives and mushrooms bring bright flavor to the creamy sauce that is made from a combination of sharp cheddar cheese and cottage cheese. And when tossed and baked spaghetti noodles, it makes this chicken spaghetti irresistible.
Every forkful tastes fresher but does not hold back on the creamy, savory, cheesy flavor that your grandma’s chicken spaghetti casserole is iconic. It just goes to show that sometimes the best recipe updates don’t reinvent a classic – they simply help it become the best version of itself!
Why You’ll Love This Chicken Spaghetti Casserole
- It’s the ultimate comfort food! There’s nothing more comforting than a dish of bubbling, cheesy noodles. The creamy vegetable sauce is packed with flavor in every bite. If chicken spaghetti casserole isn’t a staple in your kitchen, it’s about to be!
- It tastes nostalgic! If you grew up having chicken spaghetti casserole at family gatherings, this will transport you back in time. Each bite is cheesy, savory, and delicious.
- Elevated but still simple! We’re using rotisserie chicken to simplify the prep work. And even though you are using fresh vegetables for the creamy sauce, everything is thrown together in one pan, making it super easy to whip up!

Ingredients You’ll Need
- Spaghetti noodles
- Rotisserie chicken
- Red bell pepper
- Yellow onion
- Casteltrevano olives
- Mushrooms
- Chicken broth
- Shredded sharp cheddar cheese
- Cottage cheese
- Cayenne pepper
- Butter
- Flour
- Garlic
- Thyme
How to make Homemade Chicken Spaghetti Casserole, Step by Step
Step 1. Boil a pot of water and cook spaghetti noodles.Â
Start by filling a large pot of water for the pasta noodles.
Tip: You can typically use 4 quarts of water for every 16 oz of pasta.Â
Generously salt the water with a couple of tablespoons of salt. Bring the water to a boil and cook the pasta according to the package instructions. Once the pasta is al dente, strain the water from the pot and toss the pasta in a drizzle of olive oil to prevent the pasta from clumping together.
Step 2. Make a homemade cream of mushroom mixture. Let the mixture simmer to thicken.
Traditional southern chicken spaghetti casseroles call for canned cream of mushroom soup, but we wanted a fresher, more vibrant flavor that you can’t quite get with the canned stuff.Â
The good thing is that it is not hard to make at all. Start by sauteeing onions, peppers, and mushrooms in a skillet over medium heat. When they are soft and the onions are translucent, sprinkle flour in the pan to thicken the sauce.
Pour chicken broth into the pan and continue to stir the mixture until it is slightly thickened. Let the broth simmer for 3-4 more minutes until it thickens some more. Stir in the creamy cottage cheese until evenly incorporated into the sauce.

Step 3. Mix the sauce, seasoning, chicken, olives, and cheese into the cooked noodles.Â
Pour the homemade cream of mushroom mixture over the noodles and stir in shredded rotisserie chicken pieces, sliced olives, spices and shredded cheddar cheese until evenly blended.
Step 4. Pour cheesy noodles into a casserole dish, top with cheese and olives, and bake.Â
Lastly, pour the cheesy noodle mixture into a buttered casserole dish and top with extra shredded cheddar cheese.Â
Bake in the oven for 40-45 minutes until the cheese on top is browned, and the mixture is bubbling. Let it sit for 10 minutes to cool and let the flavors meld together. Use a large spoon to scoop and serve.

Tips for Making Chicken Spaghetti Casserole
- Make sure you have enough water to cook your pasta. As mentioned above, a good rule of thumb to remember is to boil 4 quarts of water for every 16 oz of water. Having enough water in your pot will prevent clumping and keep the water boiling at a temperature to cook the pasta evenly.Â
- Generously salt the pasta water. Salting the water will add flavor to the pasta. We recommend adding 2 tbsp for every 4 quarts of water.
- Blend cottage cheese for a creamy texture. Cottage cheese is used to add creaminess to the homemade cream of mushroom sauce. To get that creamy texture, blend the cottage cheese in a high-powered blender or food processor before adding it to the sauce.
- Use rotisserie chicken! It’s less work on your end and tastes delicious. You won’t have to worry about cooking your own chicken. All you have to do is remove the tender chicken from the bones and chop or shred it into fine pieces.Â
- Let the sauce thicken before combining everything. After adding the broth and flour to the cream of mushroom mixture, allow the mixture to simmer for a few minutes. This creates a creamy casserole that isn’t watery.
Recipe FAQ
How to Store Chicken Spaghetti Casserole
If you have any leftovers, store them in an airtight container. Keep in the refrigerator for up to 2-3 days. To reheat, scoop out individual portions and reheat in the microwave for in 30-second increments until warm.Â
If storing for longer, freeze for up to 2-3 months. Let the casserole dish cool completely before storing it in a freezer-safe casserole dish wrapped in plastic wrap and foil or an airtight container. Â
To reheat frozen casserole, thaw for 24-48 hours, bake at 350ºF for 30-35 minutes.

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(Better than Grandma’s) Chicken Spaghetti Casserole
- Total Time: 1 hour 20 minutes
- Yield: 12–16 servings 1x
Description
Ingredients
- 1 lb spaghetti noodles
- 1 rotisserie chicken, chicken removed and shredded
- 3 tbsp butter
- 3 tbsp all-purpose flour
- 1/3 cup red bell pepper, finely chopped
- 1/2 yellow onion, diced
- 1 cup mushrooms, chopped
- 3 cloves garlic, minced
- 2 cups chicken broth
- 2 cups shredded cheddar cheese
- 1 cup cottage cheese
- 1/2 cup Castelvetrano olives, sliced
- 1/2 tsp chili powder
- 1/2 tsp thyme
- Salt and pepper to taste
Instructions
- Boil a pot of water for pasta noodles. Salt the water and cook the pasta according to package instructions. Strain the noodles and keep them in the pot.
- In a skillet over medium heat, melt butter. Add chopped mushrooms, onions, red pepper, and garlic to the pan and sauté until soft. Season with salt and pepper. Sprinkle 3 tbsp of flour into the skillet with the vegetables. Stir to mix into the mixture and let it simmer for 1-2 minutes. The flour will thicken the sauce.
- Pour chicken broth into the pan and continue to stir the mixture as it simmers for 3-4 more minutes.
- As that is simmering, blend cottage cheese in a high-powered blender until it is smooth and creamy in texture. Pour it into the skillet with the veggie broth mixture and stir until smooth. Let it simmer for a couple more minutes.
- Add the veggie sauce to the pot with the noodles. Stir in 1 cup of shredded cheese, chili powder, and chopped olives until the cheese has started to melt, and everything is evenly mixed.
- Pour the noodle mixture into a 9×13-inch baking dish and top with 1 cup of cheddar cheese.
- Bake in preheated oven for 45-50 minutes. Let the dish sit for 10 minutes before serving. Scoop to serve.
- Prep Time: 30 minutes
- Cook Time: 50 minutes













