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Chicken Spaghetti Casserole combines spaghetti pasta, cooked chicken, and zesty vegetables in a creamy homemade sauce, plus three kinds of cheese.
Our Chicken Spaghetti Casserole is the ultimate comfort food meal. It’s a make-ahead meal that can be baked and served for a family dinner or potluck suppers.
You can make this easy casserole with mild and creamy flavors that kids and grownups both love, or amp things up a bit with spicier flavors – the choice is yours!
Why You’ll Love Chicken Spaghetti Casserole
- It’s easy to make with store-bought rotisserie chicken. Or, use home-roasted or poached chicken if you prefer.
- The tender pasta, cooked chicken, and vegetables are a complete meal-in-one.
- No canned soups involved – a simple homemade cream sauce adds great flavors and a creamy texture without processed ingredients.
Key ingredients and Substitutions
- Spaghetti – While you can use just about any other pasta type, spaghetti is the traditional choice for this casserole. Chose a thick spaghetti if available, and avoid thin angel hair or vermicelli pasta.
- Cooked chicken – You will need a total of one pound of cooked chicken meat for this recipe. Buy a large rotisserie chicken or if you have cooked chicken meat from other recipes – such as our oven-roasted chicken or poached chicken – use that.
- Vegetables – We used a combination of green bell pepper, baby Bella (Cremini) mushrooms and sweet onion, plus fresh garlic. You could substitute yellow, red or orange bell peppers instead, as well as white button mushrooms, and yellow onion if you wish.
- Diced Tomatoes – A can of drained, diced tomatoes is also used in this casserole. If you want to spice up the flavors a bit, you can use mild or spicy Rotel canned tomatoes with chilies.
- Sauce – A simple sauce is made with butter, flour, heavy cream and chicken stock or broth that is seasoned simply with salt, pepper and nutmeg
- Cheeses – This dish includes three kinds of cheese: cream cheese, yellow cheddar, and Monterey Jack cheeses.
Special supplies needed
- Large pot – to cook the spaghetti and toss the final mixture together.
- Sauté pan to pre-cook the vegetables.
How do I make Chicken Spaghetti Casserole?
- Partially cook the spaghetti. Drain, rinse, and hold for later.
- Sauté mushrooms, onion, bell pepper and garlic in olive oil.
- Make the sauce by thickening cream and chicken stock with butter and flour, then seasoning with salt, pepper, nutmeg and cream cheese.
- Combine partially cooked spaghetti with sauteed vegetables, cooked cut-up chicken, tomatoes, cream sauce, cheddar cheese, and Monterey Jack cheese.
- Pour the mixture into a deep 9x13x3-inch casserole dish.
- Bake in the oven until hot and bubbly and the cheese is melted. (Broil for a few minutes to brown the top if you’d like.)
- Remove the casserole from the oven, then allow it to rest before serving.
Chef’s Tip – A thick spaghetti typically takes around eleven minutes to reach al dente, per the box directions. For this recipe, cook four minutes less than box instructions – the pasta will cook further in the oven and absorb some of the sauce.
Frequently asked Questions
Can I make Chicken Spaghetti Casserole ahead of time? You can cook the spaghetti, cook the vegetables, and make the sauce ahead – then assemble and bake when ready. Just bring everything to room temperature for 30 minutes before baking.
How do I store leftovers? Store refrigerated and covered up to three days
How do I reheat leftovers? Microwave or place in the oven to heat through
Can I freeze? Yes, but with all pasta dishes, once thawed and heated, the texture of the pasta may be a little softer.
You may enjoy these other comfort food recipes:
- Spaghetti Pie
- Chicken Carbonara Spaghetti Pie
- Chicken Carbonara
- Baked Chicken Salad
- Italian Ham and Potato Casserole
1 pound dry spaghetti, thick version if available
3 tablespoons extra virgin olive oil, divided
8 ounces bella mushrooms, sliced
1 cup sweet onion, diced
1 cup green bell pepper, diced
1 tablespoon fresh garlic, minced
6 tablespoons butter
6 tablespoons all-purpose flour
2 cups chicken stock or broth, heated to hot (use microwave proof 2-cup glass measuring cup)
1 cup heavy cream
4 ounces cream cheese
1 teaspoon kosher salt
1/2 teaspoon white pepper
Few grinds nutmeg
1 14.5-ounce can diced tomatoes, drained
1 pound cooked chicken meat, cut into bite sized pieces
8 ounces yellow cheddar cheese, shredded and divided
8 ounces Monterey Jack cheese, shredded and divided
Preheat oven to 375 degrees F with rack in center of oven.
Spray a 9x13x3-inch deep casserole dish with kitchen pan spray and set aside.
Bring a large pot of water to a boil and salt with a teaspoon or so of kosher salt. Add spaghetti and boil four minutes less than box directions. Our box of Barilla thick spaghetti cooking directions states to boil 11 minutes. We boiled for seven minutes. Drain, rinse with cold water and set aside.
In a large saute pan, add 2 tablespoons of the olive oil and over medium high heat, saute the mushrooms for eight minutes, stirring often.
Keep the burner on medium high and push the mushrooms to the edge of the pan. Add the remaining tablespoon of oil then add the onions and pepper and cook three minutes, stirring into the mushrooms as they cook.
Add the garlic and cook one minute more then remove the pan from heat.
While vegetables are sautéing, place empty pasta pot back on the stove and over medium heat, melt the butter. Once melted, stir in the flour and cook for three minutes, stirring often with a wooden spoon.
Whisk in the heated chicken stock a little at a time to get a smooth sauce.
Whisk in the heavy cream and heat the sauce to hot.
Add the cream cheese and whisk until it melts into the sauce.
Season the sauce with the salt, white pepper and nutmeg, then remove from heat.
Add the drained canned tomatoes to the pot with the sauce along with the partially cooked spaghetti, sautéed peppers and onions mixture, cooked chicken and half of each of the cheddar and Jack cheeses.
Use tongs and a large firm rubber spatula and toss the mixture to combine.
Pour into the prepared baking dish and top with the remaining cheddar and Jack cheese and bake for 40 minutes uncovered.
Place under the broiler to brown the top then remove from the oven and let rest for 15 minutes.
As it rests, it firms up which will allow you to cut 3×4 into 12 neat even portions. Remove portions with a flexible rubber spatula and serve.
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Yellow cheddar cheese is famous for giving up some of its fat while cooking (If you ever got a greasy pizza, same thing). That fat will usually sit on top and can be easily absorbed with paper towels. Simply tear off a piece of paper towel as long as the casserole dish, gently press down across the top and lift off.