Mexican Spaghetti Squash Casserole

The first time I made this spaghetti squash casserole, my kitchen filled with the most incredible aroma of roasting vegetables and warm spices. My roommate poked her head in, convinced I'd spent hours simmering something complicated, and looked genuinely shocked when I told her most of the magic happened in the oven. Now it's become our go-to when we want something that feels indulgent but still keeps us feeling light and energized.

Last winter, I brought this to a potluck dinner and watched it disappear in record time. My friend's husband, who claims to despise anything with squash in the name, went back for thirds and finally admitted he'd been wrong. There's something about the combination of melting cheese, hearty beans, and that slightly sweet squash that converts even the most skeptical eaters.

Ingredients

• 1 large spaghetti squash: This becomes the star of the show, transforming into tender strands that mimic pasta while bringing natural sweetness and fewer carbs
• 1 medium red bell pepper, diced: Adds beautiful color and a subtle sweetness that balances the smoky spices
• 1 small red onion, diced: Provides a savory base that caramelizes beautifully during roasting
• 2 cloves garlic, minced: Fresh garlic is non-negotiable here for that aromatic punch
• 1 jalapeño, seeded and minced (optional): Leave it in if you like some gentle heat, remove it for sensitive palates
• 1 cup frozen corn kernels, thawed: Brings little bursts of sweetness and texture throughout
• 1 can (15 oz) black beans, drained and rinsed: The protein backbone that makes this satisfying enough for a main course
• 1 can (14 oz) diced tomatoes, drained: Use fire-roasted if you can find them for extra depth
• 1½ tsp ground cumin: Earthy and essential for that classic Mexican flavor profile
• 1 tsp chili powder: Adds warmth without overwhelming heat
• 1 tsp smoked paprika: The secret ingredient that gives this dish its irresistible smoky undertone
• ½ tsp dried oregano: Brings a subtle herbal note that ties all the spices together
• ½ tsp salt and ¼ tsp black pepper: Adjust these to taste, but don't skip them entirely
• 1 cup shredded cheddar cheese: Sharp cheddar provides that perfect cheesy punch
• ½ cup shredded Monterey Jack cheese: Melts beautifully and complements the sharper cheddar
• ¼ cup chopped fresh cilantro: Fresh herbs at the end brighten everything up
• 1 lime, cut into wedges: A squeeze of lime right before serving makes all the flavors pop

Instructions

Roast the squash:

Preheat your oven to 400°F and line a baking sheet with parchment. Cut that spaghetti squash in half lengthwise, scoop out the seeds, give the cut sides a quick brush of olive oil, and place them cut-side down. Let them roast for 35 to 40 minutes until the flesh yields easily when you poke it with a fork.

Sauté the vegetables:

While the squash does its thing, heat a splash of olive oil in a large skillet over medium heat. Toss in the onion, bell pepper, jalapeño if you're using it, and garlic. Cook them for 4 to 5 minutes until they've softened and your kitchen smells amazing.

Build the filling:

Add the corn, black beans, and drained tomatoes to the skillet. Sprinkle in all those spices, cumin, chili powder, smoked paprika, oregano, salt, and pepper. Let everything cook together for another 3 to 4 minutes, stirring occasionally so the spices bloom and coat everything evenly.

Shred and combine:

Once the squash is cool enough to handle, grab a fork and shred that flesh into strands. Reduce your oven temperature to 375°F. In a large mixing bowl, toss the shredded squash with your vegetable-bean mixture and stir in half of both cheeses.

Bake to golden perfection:

Transfer everything to a lightly greased 9x13-inch casserole dish and spread it evenly. Sprinkle the remaining cheese across the top like a cozy blanket. Bake for 20 to 25 minutes until the casserole is hot throughout and the cheese is bubbling and turning golden brown in spots.

Finish with fresh touches:

Scatter that fresh cilantro over the top and serve with lime wedges on the side so everyone can add a bright squeeze right before digging in.

Save

This recipe started as a way to use up vegetables from my CSA box, but it's evolved into something I crave even when I'm not trying to be virtuous. There's something deeply satisfying about how it comes together, layers of flavor building on each other until you end up with this bubbling, golden dish that makes the whole house feel cozy.

Make It Your Own

I've discovered that this casserole is incredibly forgiving. Add shredded chicken or ground turkey if you want extra protein, or swap in pinto beans instead of black beans for a different twist. Sometimes I throw in diced zucchini or extra bell peppers when I need to use up produce.

Serving Suggestions

A simple green salad with a lime vinaigrette cuts through the richness perfectly. I also love serving this with sliced avocado, a dollop of sour cream, or some pickled jalapeños on the side. It's hearty enough to stand alone but plays nicely with whatever Mexican-inspired sides you have on hand.

Storage And Reheating

This casserole keeps beautifully in the refrigerator for up to four days. I actually think the flavors improve overnight as everything melds together. Reheat individual portions in the microwave or cover the whole dish with foil and warm it in a 350°F oven until heated through.

• Portion it into individual containers before refrigerating for easy grab-and-go lunches
• If freezing, wrap it tightly and it will keep for up to three months
• Thaw overnight in the refrigerator before reheating for the best texture

Save

There's something so satisfying about a dish that feels indulgent but still leaves you feeling good. This casserole has become one of those recipes I turn to again and again, a reliable favorite that never fails to make dinner feel special.

Recipe FAQs

→ Can I make this casserole ahead of time?

Yes, you can assemble the entire casserole up to 24 hours in advance and refrigerate it before baking. You may need to add a few extra minutes to the baking time if baking it cold from the refrigerator.

→ How do I store leftovers?

Store leftover casserole in an airtight container in the refrigerator for up to 4 days. Reheat individual portions in the microwave or cover the 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 it 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 casserole?

This casserole is complete as a meal on its own, but you can serve it with a simple green salad, guacamole, sour cream, or additional tortillas for a more substantial spread.

→ Is this dish spicy?

The spice level is mild to medium, coming from the chili powder and optional jalapeño. You can adjust the heat by reducing the chili powder or omitting the jalapeño for a milder version.

→ Can I use other types of squash?

While spaghetti squash works best for its strand-like texture, you could use butternut or acorn squash diced into small pieces. The cooking time may vary slightly depending on the squash variety.