Mexican Spaghetti Squash Casserole

The first time I made this, my roommate walked in mid-roast and demanded to know what smelled like a Mexican restaurant took over our apartment. Now it is the Tuesday night dinner that actually makes people look forward to the week.

Last winter my sister claimed she hated spaghetti squash, then went back for thirds and quietly asked for the recipe before she even left the house.

Ingredients

• 1 large spaghetti squash: Pick one that feels heavy for its size with a firm, unblemished skin because this vegetable does all the heavy lifting
• 1 medium red bell pepper, diced: The sweetness balances the spices perfectly so do not skip it
• 1 small red onion, diced: Red onion has a milder bite that works beautifully here
• 2 cloves garlic, minced: Fresh garlic makes a noticeable difference over the jarred stuff
• 1 jalapeño, seeded and minced: Leave some seeds if you want extra heat because the dairy tames it anyway
• 1 cup frozen corn kernels, thawed: Adds little bursts of sweetness throughout
• 1 can (15 oz) black beans, drained and rinsed: Rinse them well to avoid any metallic taste from the canning liquid
• 1 can (14 oz) diced tomatoes, drained: Really drain them well or your casserole will end up soupy
• 1½ tsp ground cumin: This is the backbone flavor so do not be shy with it
• 1 tsp chili powder: Use a good quality chili powder for the best flavor
• 1 tsp smoked paprika: This adds an almost meaty depth even though the dish is vegetarian
• ½ tsp dried oregano: Mexican oregano is traditional but regular works fine
• ½ tsp salt: Adjust based on whether your cheese is particularly salty
• ¼ tsp black pepper: Freshly ground makes a real difference here
• 1 cup shredded cheddar cheese: Sharp cheddar gives the best flavor punch
• ½ cup shredded Monterey Jack cheese: This melts beautifully and creates that gorgeous cheese pull
• ¼ cup chopped fresh cilantro: The bright herbal finish cuts through all that rich cheese
• 1 lime, cut into wedges: A squeeze of lime right before serving makes everything pop

Instructions

Get your oven going:

Preheat to 400°F and line a baking sheet with parchment paper for easy cleanup later

Roast the squash:

Cut it lengthwise, scoop out the seeds, brush with olive oil, and place cutside down for 35 to 40 minutes until tender

Sauté the vegetables:

Cook onion, bell pepper, jalapeño, and garlic in olive oil for 4 to 5 minutes until softened and fragrant

Build the filling:

Stir in corn, beans, tomatoes, and all those spices then cook for another 3 to 4 minutes

Shred the squash:

Let it cool enough to handle then use a fork to pull out all those strands and reduce the oven to 375°F

Combine everything:

Mix the squash with the vegetable filling and half of both cheeses in a large bowl

Assemble the casserole:

Transfer to a 9x13-inch dish and scatter the remaining cheese across the top

Bake until bubbly:

Pop it in for 20 to 25 minutes until everything is hot and the cheese is golden and irresistible

Finish with flair:

Sprinkle with fresh cilantro and serve with those lime wedges for squeezing over each portion

Save

This recipe has become my go-to for new parents because it reheats beautifully and tastes like comfort food but leaves everyone feeling energized instead of heavy.

Making It Your Own

I started adding a can of diced green chilies when I want extra depth without much more effort, and sometimes I throw in some zucchini during the vegetable sauté phase if my garden is overflowing.

Serving Ideas

A simple green salad with a lime vinaigrette cuts through the richness perfectly, and warm tortillas on the side make it feel even more like a fiesta. My friend serves it over cauliflower rice for an extra veggie boost.

Storage and Meal Prep

This casserole keeps beautifully in the refrigerator for up to five days and actually benefits from the flavors melding together. I often make it Sunday and portion it out for easy lunches throughout the week.

• Freeze individual portions for those nights when cooking feels impossible
• Recover with a splash of water and cover with foil so it does not dry out
• The texture holds up surprisingly well after freezing

Save

This is the kind of comfort food that makes you forget you are eating something so wholesome and nutritious. Enjoy every cheesy, spicy bite.

Recipe Questions & Answers

→ Can I make this casserole ahead of time?

Yes, you can assemble the entire casserole up to 24 hours in advance and store it covered in the refrigerator. When ready to bake, you may need to add a few extra minutes to the baking time since it will be cold.

→ How do I store leftovers?

Store leftover portions in an airtight container in the refrigerator for 3-4 days. Reheat individual portions in the microwave or cover the entire dish with foil and warm in a 350°F oven until heated through.

→ Can I freeze this casserole?

Yes, this freezes well. Assemble the casserole, wrap tightly with plastic wrap and foil, and freeze for up to 3 months. Thaw overnight in the refrigerator before baking as directed.

→ What can I serve with this dish?

Pair with a simple green salad, Mexican rice, or tortilla chips. Fresh toppings like sliced avocado, sour cream, pickled jalapeños, or extra cilantro add wonderful contrast to the warm, cheesy casserole.

→ Is this dish spicy?

The spice level is mild to medium. The jalapeño is optional, so you can control the heat. The chili powder and spices add flavor without excessive heat. Adjust the amount of jalapeño or add hot sauce at the table if desired.