
This Monterey spaghetti bake is the ultimate pasta recipe! Once you try this crowd-pleasing dinner, you’ll understand why it’s a family favorite.
It’s creamy, cheesy, and packed with little surprises like spinach and crispy French-fried onions. Each bite is better than the last.
It’s a delicious, easy casserole that effortlessly balances rich flavors and satisfying textures.
Don’t be ashamed if you come back for thirds!
Ingredients
- Spaghetti Noodles: The hearty, satisfying base of the casserole. It holds the creamy, cheesy mixture together.
- Eggs: They help bind the ingredients for a rich, cohesive texture throughout the dish.
- Sour Cream: It adds creaminess and a tangy flavor. It also balances the richness of the cheeses.
- Parmesan Cheese: It offers a savory, nutty taste that enhances the overall depth of flavor.
- Garlic: It infuses the dish with a subtle yet aromatic punch of flavor. Avoid garlic powder; stick to freshly minced instead.
- Shredded Monterey Jack Cheese: It melts beautifully into the casserole for a mild, creamy, and slightly sweet cheesiness.
- Frozen Chopped Spinach: It provides a pop of color, nutrients, and earthy flavor. It complements the richness of the cheese quite nicely, as well. If using fresh spinach, you’ll need about 16 ounces of raw spinach to make 10 ounces of cooked.
- French-Fried Onions: Crispy fried onions are the crunchy, savory topping. They add texture and a burst of flavor to every bite.
How to Make Monterey Spaghetti
- 1. PREPARE.
- Preheat the oven to 350 degrees Fahrenheit. Grease a 9×13-inch baking dish. Set aside.
- 2. COOK SPAGHETTI.
- Cook it in a large pot of salted, boiling water. Cook according to the package directions until al dente, then drain and set aside.
- 3. MIX BASE.
- Whisk the eggs in a large bowl until smooth. Then, stir in the sour cream, Parmesan cheese, and minced garlic.
- 4. COMBINE.
- Add the slightly cooled cooked spaghetti to the egg mixture and toss to coat. Fold in the shredded Monterey Jack, chopped spinach, and one of the cans of French onions. Mix well.
- 5. ASSEMBLE.
- Spread the mixture evenly into the baking dish and cover with aluminum foil.
- 6. BAKE.
- Bake, covered, for 30 minutes. Then, uncover and sprinkle the remaining onions on top. Bake for another 5 minutes, uncovered, until the crispy fried onions are crisp and golden brown.
- 7. SERVE.
- Remove the casserole from the oven and let it rest for a few minutes. Then, enjoy!

Tips for the Best Monterey Spaghetti
These tips and tricks will make your spaghetti sensational.
Don’t overcook the pasta! Boil it until it’s just tender, then drain it immediately. It’ll keep cooking in the oven, so you don’t want to fully cook it initially.
Don’t get scrambled. Don’t add the hot pasta to the egg mixture, or it could scramble the eggs. Instead, set it aside to let it cool slightly first.
Ditch the excess liquid. Squeeze as much liquid as possible from the thawed spinach using a kitchen towel. Excess moisture can make the casserole watery.
Skip the bagged stuff. Pre-shredded cheeses aren’t the way to go. They often contain anti-caking agents that can negatively affect the casserole’s texture. Shred the Monterey Jack and grate the Parmesan cheese yourself.
Boost the flavor. Lightly saute the minced garlic for 1 to 2 minutes before mixing it in. Doing so will give the spaghetti bake a deeper, sweeter garlic flavor. For a bit of heat, stir in a pinch of crushed red pepper flakes or diced jalapeno.
Experiment and have fun. Try replacing some of the Monterey Jack cheese with mozzarella for stretchiness. (Or sharp cheddar for a tangier flavor.) You can also swap out frozen spinach for fresh spinach or other greens. (i.e., kale, Swiss chard, or broccoli.) Add-ins like shredded chicken, sun-dried tomatoes, or bacon work well, too.

How to Store
Monterey spaghetti stores well, but you can’t freeze it. The texture won’t hold up once it thaws.
To Store: Let the leftovers cool completely. Then, refrigerate them in an airtight container for up to 4 days.
To Reheat: Reheat desired portions covered in the oven. (350 degrees/15-20 minutes) Or microwave on high for 1 to 2 minutes. Add a sprinkle of fresh cheese on top for extra melty goodness. If the mixture seems dry, add a splash of chicken broth.
Frequently Asked Questions
- → Can I use fresh spinach instead of frozen?
Yes, substitute about 16 ounces of fresh raw spinach for 10 ounces of frozen cooked spinach. Be sure to wilt and drain excess moisture before mixing.
- → How do I prevent the eggs from scrambling?
Allow cooked spaghetti to cool slightly before mixing with the egg and sour cream base. This avoids overheating the eggs and keeps the texture smooth.
- → What is the best way to store leftovers?
Cool leftovers completely, then refrigerate in an airtight container for up to 4 days. Reheat covered in the oven or microwave with a splash of broth if dry.
- → Can I freeze the casserole?
Freezing is not recommended as the texture may become watery and change upon thawing.
- → How can I enhance the garlic flavor?
Lightly sauté minced garlic for 1-2 minutes before mixing into the base for a sweeter, deeper garlic aroma.
- → Are there any good add-ins to vary the dish?
Try adding shredded chicken, sun-dried tomatoes, bacon, or swap some Monterey Jack for mozzarella or sharp cheddar for different flavor profiles.