
This Monterey Chicken Spaghetti is pure comfort food. It's loaded with juicy chicken, lots of spinach, and gooey cheese all mixed up with spaghetti noodles. Crispy onions add a yummy crunch on top, making every forkful cozy and satisfying—perfect for a busy weeknight or a friendly get-together.
The first time I brought this dish to a family event every picky eater wanted seconds. Now it's a regular for our Sunday dinners—and if I skip a month it gets requested again!
Hearty Ingredients
- French fried onions: super crispy and salty—use half mixed in and the rest for the top for extra crunch
- Onion powder: tosses in mellow onion flavor without the fuss of chopping
- Cream of chicken soup: keeps everything creamy and cozy, so grab a quality can with less salt if you find one
- Garlic: fresh cloves add oomph, but go with powder if that's all you've got
- Chopped spinach: brightens it up with greens and nutrients—squeeze dry to prevent sogginess
- Egg: makes sure everything holds together—just whip it up before adding
- Sour cream: keeps it tangy and creamy—full fat is tastiest
- Parmesan cheese: grated real Parmigiano Reggiano adds a sharp, nutty bite
- Monterey Jack cheese: melts smooth and rich—grate it yourself if you can
- Cooked chicken breasts: juicy and shredded is best—try not to overcook it
- Spaghetti: go with classic Italian pasta, boil just until gently firm
Simple Steps
- Add Crispy Topping:
- Once it's baked for half an hour, pull off the foil. Scatter the last bit of fried onions all over. Pop it back in for five minutes, so the onions get extra crunchy and dark golden—but keep an eye out so they don't get too dark.
- Bake the Casserole:
- Spread a little oil or butter in a 9x13 dish. Fill it with the spaghetti mixture and smooth it out. Snugly wrap with foil and bake at 350 F for half an hour so it's gooey and melded together.
- Combine with Pasta:
- Take your drained spaghetti and dump it into the bowl with all that creamy, cheesy filling. Toss until everything's coated and the chicken and spinach are all throughout. Go easy so the pasta doesn't break up.
- Mix the Filling:
- Grab a big bowl. Whisk the egg until it's fluffy to help hold things together. Dump in your chicken, sour cream, soup, both cheeses, well-squeezed spinach, half those onions, garlic, and onion powder. Stir like crazy—it'll be a thick, creamy mix.
- Cook Spaghetti:
- Boil pasta in lots of salted water following the box directions. Stir every now and then so it doesn't stick, and cook it a little firm—not soft. Drain well. Don't cook it too long or it'll get mushy when baked.

I always get excited pulling this out of the oven and smelling those toasty crispy onions. Parmesan makes it extra special with that hint of nuttiness. Every time, it takes me back to sneaking extra cheese with my grandma—it was always our little tradition.
Storing Leftovers
Let it cool to room temp before you pack it up. Either wrap tight with foil or use an airtight dish. It'll keep in the fridge for up to four days. For longer, freeze single portions wrapped in plastic then foil, and reheat at 350 F until piping hot. Fried onions can lose their crunch after freezing, so I sometimes just add a quick fresh sprinkle before popping it back in the oven.
Switching Things Up
Rotisserie chicken is a fast swap, or use canned chicken if that's what's in the pantry. Want it lighter? Try cottage cheese instead of sour cream. You can also sub in mozzarella or Swiss for Monterey Jack. Leave out the chicken for a veggie version—just cook up mushrooms and a bit more garlic.
How to Serve
This dish is great with a tangy green salad with lots of lemon. Garlic bread is always a hit on the side. For something brighter, add a scoop of zippy marinara to each plate, or toss cherry tomatoes in before baking.

Origins and Traditions
This dish is a cozy twist on the classic Midwest and Southern casseroles found at potlucks everywhere. That creamy soup and crisp onion combo is a nod to traditional holiday green bean bakes. It's the kind of comfort food that fills the table and brings everyone together for a hearty meal.
Frequently Asked Questions
- → Can I use rotisserie chicken instead of cooked chicken breasts?
Totally! Grab a rotisserie chicken if you want easy, tasty chicken in this pasta bake.
- → How can I prevent the spinach from being watery?
Fully thaw your spinach and squeeze it super dry with paper towels so your pasta stays nice, not soggy.
- → Is it possible to substitute cheeses?
Go with mozzarella or cheddar if you don't have Monterey Jack, or swap in asiago or pecorino for parmesan—do what you like.
- → Can this pasta dish be made ahead?
Sure can! Put it together a day early, pop it in the fridge, then bake it up with the fried onions when you're set to eat.
- → What’s the best way to reheat leftovers?
Just cover and warm it in a 325°F oven till it's hot. If you want those onions extra crispy, add some fresh ones after heating.