Chicken Spaghetti Casserole
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Creamy sauce from a skillet, tender spaghetti, and cheddar baked until it browns at the corners. Take it to a potluck and the dish comes home scraped clean, with at least one person asking for the recipe.
The short version
Cook spaghetti 2 minutes short. Sauté peppers, onion and mushrooms, make a quick butter-flour-broth-cream sauce, and stir in shredded rotisserie chicken, spaghetti and Parmesan. Top with cheddar and bake at 350°F until bubbly, about 30 minutes. Total 1 hour.
What makes ours better
small changes, very loud compliments
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Make the sauce from scratch. Five minutes of butter, flour, broth and half-and-half beats canned soup. You control the salt, and the flavor tastes of mushrooms and onion rather than the can.
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Undercook the spaghetti by 2 minutes. The noodles keep absorbing sauce in the oven. Pasta cooked to al dente goes soft and mushy by the time the casserole is done.
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Use rotisserie chicken. A store-bought chicken gives you seasoned, juicy meat in the time it takes the water to boil.
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Add cream cheese to the sauce. It makes the sauce rich and stable, so it stays creamy through baking and reheating.
What you need
check the pantry before you promise anyone
- Spaghetti12 ounces
- Shredded cooked chicken3 cups
- Red bell pepper1 medium
- Cremini mushrooms8 ounces
- Half-and-half1 cup
- Cream cheese4 ounces
- Sour cream½ cup
- Finely grated Parmesan½ cup
Casserole
Sauce
Topping
tap each one as it goes in. no double-salting.
Steps
go slow. the good part can’t be rushed.
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Heat the oven, boil water
Set a rack in the middle of the oven and heat it to 350°F. Grease a 9×13-inch baking dish. Bring a large pot of salted water to a boil.
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Cook the spaghetti
Cook the spaghetti 2 minutes less than the package says, until it's still firm in the center. Drain it without rinsing and leave it in the colander.
Pasta that tastes done now will be mush after baking.
About 8 min. Cook mode has a timer for this step.
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Soften the vegetables
Melt the butter in a large, deep skillet over medium heat. Add the onion, bell pepper and mushrooms with a pinch of salt. Cook 6 to 8 minutes, stirring now and then, until the mushrooms release their liquid and it cooks off. Add the garlic and cook 30 seconds.
About 8 min. Cook mode has a timer for this step.
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Make the sauce
Sprinkle the flour over the vegetables and stir for 1 minute, until no dry flour shows. Slowly pour in the broth, then the half-and-half, stirring. Simmer for 3 to 4 minutes, until it thickens enough to coat a spoon.
Add the liquid slowly at first. Dumping it in all at once leaves lumps.
About 4 min. Cook mode has a timer for this step.
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Melt in the creamy parts
Turn the heat to low and stir in the cream cheese until it disappears. Off the heat, stir in the sour cream, salt, pepper and Parmesan. Taste and add salt if needed.
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Combine
Fold the chicken and spaghetti into the sauce until every strand is coated. The mixture should look quite saucy. If it seems dry, add a splash of broth.
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Top and bake
Scrape into the baking dish and spread evenly. Cover with the cheddar. Bake 25 to 30 minutes, until the sauce bubbles at the edges and the cheese is melted and spotted with gold.
About 28 min. Cook mode has a timer for this step.
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Rest and serve
Let the casserole stand for 10 minutes so the sauce thickens and clings. Sprinkle with parsley and scoop.
About 10 min. Cook mode has a timer for this step.
Good to know
read this before somebody asks for seconds
- Short on time? Skip the vegetables and sauce steps. Use two 10.5-ounce cans of cream of mushroom soup, 1¼ cups broth, and the sour cream. It's less fresh, but it works.
- Make it ahead. Assemble without baking, cover, and refrigerate up to 24 hours. Bake 35 to 40 minutes, or until bubbly in the center.
- Add a can of drained diced tomatoes with green chiles for a Tex-Mex version, or swap in a cup of frozen peas for color.
- A broiler for 1 to 2 minutes at the end browns the cheese. Watch it closely.
- Storage. Covered in the fridge, 4 days. Freezer, up to 3 months in a covered dish. Thaw overnight and reheat at 350°F, covered, for 25 to 30 minutes, adding a splash of broth if dry.
Questions, answered
asked and answered at the kitchen counter
Can I make chicken spaghetti ahead of time?
Yes. Assemble it up to 24 hours ahead and refrigerate, covered. Bake it straight from the fridge, adding 10 minutes to the time.
Why is my chicken spaghetti dry?
The pasta absorbed the sauce. Undercook the noodles, keep the mixture looking a bit saucy before baking, and cover leftovers with a splash of broth when you reheat.
Can I freeze chicken spaghetti?
Yes. Cool it completely, wrap it tightly, and freeze for up to 3 months. Thaw it overnight in the fridge before reheating.
Can I use leftover or poached chicken?
Yes. Use about 3 cups of shredded cooked chicken, breast or thigh. Poach 1½ pounds chicken in salted water for 15 to 20 minutes, until it reads 165°F, then shred.
Can I make it without canned soup?
That's how this version is made. The skillet sauce takes 10 minutes and gives better flavor and less sodium.
From the table
Made it? Tell me everything. Especially if somebody said it was better than their mother’s. I’ll keep your secret.
Made it?
tell me the truth, then tell me who had thirds
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Published October 29, 2026.