Baked Chicken Spaghetti – Creamy, Cheesy, and Weeknight-Worthy

Few things satisfy like a bubbling, golden-brown pasta bake straight from the oven.

This Baked Chicken Spaghetti is a comforting combination of tender chicken, creamy cheese sauce, zesty tomatoes, and perfectly cooked spaghetti—all topped with melted mozzarella.

Whether you’re feeding a hungry family or prepping for leftovers, this cheesy chicken casserole delivers on all fronts: easy, hearty, and packed with flavor.

Why You’ll Love This Recipe

Ultra-creamy sauce – Made with cream cheese, cheddar, and milk

Perfect for using leftover chicken – Or cook it fresh in one skillet

Cheesy baked top – With bubbly mozzarella and a golden finish

Easy to prep ahead – Great for meal prep and freezer-friendly

Customizable spice level – Add more red pepper or mild it down for kids

One dish wonder – Everything cooks together for max flavor and minimal cleanup

What You’ll Need (Ingredient Highlights)

Chicken breasts – Sliced and seared for tender bites

Italian seasoning, salt & pepper – Simple seasoning to boost flavor

Onion & garlic – Build savory depth in the sauce

Butter & flour – Create a roux for a thick, creamy base

Chicken broth & milk – Lightens the sauce without sacrificing creaminess

Cream cheese & cheddar – Rich, melty, and full of comfort

Diced tomatoes & green chilies – Adds brightness and a little zing

Thin spaghetti – Twirls beautifully into the cheesy sauce

Mozzarella cheese – For that perfectly melty baked topping

Red pepper flakes & parsley – Optional but delicious garnishes

Pro Tips Before You Start

Soften your cream cheese – Cold cream cheese won’t melt as easily

Use freshly shredded cheese – Melts smoother than pre-shredded

Cook spaghetti just shy of al dente – It will finish cooking in the oven

Don’t skip the fond – Those browned chicken bits add amazing flavor to the sauce

Broil at the end – Just a minute or two adds a gorgeous golden top

How to Make Baked Chicken Spaghetti

Step 1: Prep the Chicken

Preheat your oven to 400°F (204°C).

Slice 2 small boneless chicken breasts in half horizontally to make 4 thinner cutlets.

Pat dry and season with Italian seasoning, salt, and pepper.

In a large pot or deep skillet, heat 2 Tbsp olive oil over medium-high.

Sear the chicken for 5–6 minutes per side until cooked through.

Remove and set aside to cool, then dice into bite-sized pieces.

Step 2: Start the Sauce

In the same pot, reduce heat to medium-low.

Add 4 Tbsp butter and deglaze the fond (the flavorful browned bits) with a spatula.

Add 1 diced yellow onion and sauté for 4 minutes until softened.

Stir in 3 cloves minced garlic and cook for 1 more minute.

Step 3: Make It Creamy

Sprinkle in 4 Tbsp flour and stir to coat the onions.

Cook for 2 minutes until the flour smell disappears.

Slowly whisk in 1½ cups chicken broth, followed by ¾ cup milk, adding a bit at a time and whisking well between additions. Simmer gently.

Now’s the perfect time to start boiling a pot of water for the 8 oz thin spaghetti.

Cook according to package directions, then drain.

Step 4: Add the Cheese & Chicken

Once the sauce has thickened slightly, stir in 4 oz softened cream cheese until fully melted and smooth.

Turn heat to low, let it cool a bit, then stir in 1 cup shredded cheddar until melted.

Drain 10 oz diced tomatoes & green chilies, or stir in with some juice if you like it looser.

Add the diced chicken and stir everything together.

Step 5: Combine with Pasta & Bake

Add the cooked spaghetti to the sauce and toss to coat evenly.

If your pot isn’t oven-safe, transfer everything to a greased 9×13-inch casserole dish.

Top with 1 cup shredded mozzarella cheese.

Step 6: Bake and Broil

Bake uncovered for 15 minutes at 400°F, then broil for 1–2 minutes at 475°F to lightly brown the top.
Remove from the oven, sprinkle with red pepper flakes and chopped parsley, and serve hot with garlic bread.

What to Serve It With

Garlic bread or cheesy toast – Ideal for scooping up every bit of sauce

Crisp green salad – Adds freshness and balance

Roasted zucchini or asparagus – Light veggie sides work well

Steamed broccoli – A classic comfort pairing

Sparkling water or white wine – For an elegant dinner vibe

Variations / Substitutions

Use rotisserie or leftover chicken – Saves time and still tastes amazing

Swap cheeses – Try pepper jack, Monterey Jack, or gouda for new flavor profiles

Add spinach or kale – Stir in greens before baking for extra nutrition

Use penne or fusilli – Works well if you don’t have spaghetti on hand

Make it spicier – Add hot sauce or diced jalapeños to the sauce

Storage & Reheating Tips

Fridge – Store leftovers in an airtight container for up to 4 days

Reheat – In the oven at 350°F or microwave in short bursts with a splash of milk

Freeze – Freeze unbaked or fully baked casserole for up to 2 months

Make ahead – Assemble everything up to the baking step, then bake fresh when ready

Avoid overbaking – It can dry out the pasta; cover loosely if reheating in the oven

FAQs

Can I use pre-cooked chicken?

Yes! Rotisserie chicken or leftover grilled chicken works perfectly.

What kind of pasta works best?

Thin spaghetti is ideal, but you can use angel hair, penne, or rotini.

Do I have to bake it?

Technically no, but baking melts the mozzarella topping and brings everything together.

How can I make it healthier?

Use low-fat milk, reduced-fat cheeses, and whole wheat pasta.

Can I make this spicy?

Yes—add crushed red pepper to the sauce or use spicy diced chilies.

Can I use a different cream cheese?

Yes, regular, light, or whipped cream cheese all work. Soften it before adding.

Is this freezer-friendly?

Absolutely! Assemble it and freeze before baking or after—it reheats beautifully.

Final Thoughts

This Baked Chicken Spaghetti is a cozy, creamy casserole that hits all the right notes.

It’s cheesy without being too heavy, flavorful without being complicated, and easy enough for busy weeknights.

Whether you’re serving a family dinner or prepping meals ahead, this dish always satisfies—and you’ll probably want seconds.