Mexican Squash Casserole – Cheesy, Hearty, and Packed with Flavor
When comfort food meets fresh vegetables and bold Mexican flavors, you get a dish like Mexican Squash Casserole — a vibrant, cheesy, and satisfying bake that’s equal parts wholesome and indulgent. This recipe features tender yellow squash and zucchini layered with sweet corn, tomatoes, black beans, and a melty cheese topping, all brought together with warm spices and creamy sauce. It’s the perfect way to bring a twist to traditional squash casseroles, adding a south-of-the-border flair to your dinner table.
Whether you’re looking for a meatless main dish, a hearty side, or a creative way to use up your summer squash, this casserole delivers. It’s easy to make, feeds a crowd, and can be prepped ahead — ideal for family dinners, potlucks, or busy weeknights when you want something comforting without spending hours in the kitchen.
In this post, you’ll get detailed instructions, time-saving tips, flavorful variations, and answers to the most common questions so you can make this casserole exactly the way you like it — spicy or mild, creamy or lean, simple or loaded with extra veggies.
Why You’ll Love This Mexican Squash Casserole
- Comforting, cheesy, and full of flavor
- Uses fresh, seasonal ingredients
- Vegetarian and gluten-free friendly
- Easy to make ahead and reheat
- Customizable with your favorite add-ins
- Works as a main dish or a side
Ingredients You’ll Need
This recipe uses simple ingredients you can find at any grocery store. The combination of vegetables, spices, beans, and cheese makes it both hearty and nourishing.
Fresh Produce:
- 2 medium zucchini, sliced
- 2 medium yellow squash, sliced
- 1 small onion, diced
- 2 cloves garlic, minced
- 1 cup fresh or frozen corn kernels
- 1 medium tomato, chopped (or 1 cup canned diced tomatoes)
Canned or Jarred Goods:
- 1 (15-ounce) can black beans, drained and rinsed
- 1 (4-ounce) can diced green chiles (optional, for mild heat)
- 1 cup salsa (your favorite variety)
- 1/4 cup sour cream or plain Greek yogurt
Pantry Staples & Spices:
- 2 tablespoons olive oil or butter
- 1 teaspoon ground cumin
- 1 teaspoon chili powder
- 1/2 teaspoon smoked paprika
- Salt and pepper, to taste
Cheese & Toppings:
- 1 1/2 cups shredded cheddar cheese (or Mexican blend)
- 1/4 cup crumbled cotija cheese (optional)
- Fresh cilantro, chopped (for garnish)
Optional Add-Ins:
- Cooked rice or quinoa (for extra bulk)
- Diced bell peppers or jalapeños
- Shredded cooked chicken or taco-seasoned ground turkey
How to Make Mexican Squash Casserole
Step 1: Preheat and Prepare
Preheat your oven to 375°F (190°C). Grease a 9×13-inch baking dish with oil or nonstick spray.
Wash and slice the zucchini and yellow squash into thin rounds (about 1/4 inch thick). Dice the onion and garlic. If using fresh corn, remove the kernels from the cob. If frozen, measure and thaw.
Step 2: Sauté the Vegetables
In a large skillet, heat the olive oil over medium heat. Add the onion and cook for 3 to 4 minutes until softened. Add the garlic, zucchini, and yellow squash. Sauté for another 5 to 6 minutes, stirring occasionally, until the squash begins to soften but is not fully cooked. Season with salt, pepper, cumin, chili powder, and paprika.
Add the corn, black beans, green chiles (if using), and chopped tomato. Stir to combine and cook for 2 more minutes. Remove from heat.
Step 3: Assemble the Casserole
In a large mixing bowl, combine the sautéed vegetable mixture with salsa and sour cream. Stir until everything is evenly coated.
Spoon half the mixture into the prepared baking dish and spread into an even layer. Sprinkle with half of the shredded cheese. Add the remaining vegetable mixture on top, then finish with the remaining cheese.
If desired, top with crumbled cotija cheese for an extra layer of flavor.
Step 4: Bake
Cover the casserole with foil and bake for 20 minutes. Remove the foil and bake for an additional 10 to 15 minutes, or until the cheese is melted, bubbly, and starting to brown around the edges.
Remove from the oven and let sit for 5 to 10 minutes before serving to allow the casserole to set.
Step 5: Garnish and Serve
Sprinkle with fresh chopped cilantro and serve hot. You can also add a dollop of sour cream, extra salsa, or hot sauce for added flavor.
Tips for the Best Mexican Squash Casserole
- Slice squash evenly for even cooking
- Don’t overcook the squash during sautéing — it will finish cooking in the oven
- Use salsa you enjoy, since it flavors the whole dish
- Let the casserole sit after baking to firm up
- Adjust spice levels by choosing mild or spicy salsa and adding or skipping chiles
Flavor Variations
This recipe is endlessly flexible. Here are some easy ways to make it your own.
With Rice or Quinoa:
Add 1 to 1½ cups cooked rice or quinoa to the mix before baking. This stretches the dish and makes it even more filling.
Add Protein:
Stir in cooked shredded chicken, taco-seasoned ground beef, or spicy chorizo for a meaty version.
Go Vegan:
Use dairy-free sour cream and vegan cheese, or skip both for a lighter casserole. Add avocado on top after baking for creaminess.
Make It Spicier:
Add diced jalapeños, chipotle in adobo, or hot sauce to the vegetable mix. Choose a hot salsa for extra heat.
Add More Veggies:
Bell peppers, spinach, mushrooms, or even kale can be sautéed along with the squash to boost nutrition and flavor.
What to Serve with Mexican Squash Casserole
This casserole can stand on its own or be paired with a variety of sides. Here are a few serving ideas:
As a Main Dish:
- Serve with warm tortillas or tortilla chips
- Pair with a green salad with lime vinaigrette
- Add avocado slices or guacamole on top
- Spoon over rice for a burrito bowl-style meal
As a Side Dish:
- Serve alongside grilled chicken or steak
- Pair with enchiladas, tacos, or burritos
- Add to a brunch spread with eggs and roasted potatoes
Storage and Meal Prep
Refrigerator:
Store leftovers in an airtight container for up to 4 days. The flavors get even better the next day.
Freezer:
You can freeze the fully baked and cooled casserole in freezer-safe portions for up to 2 months. Thaw overnight in the refrigerator before reheating.
Reheating:
Reheat in a 350°F oven until warmed through, or use the microwave in 1-minute intervals. Add a splash of broth or water if it seems dry.
Make Ahead:
You can prepare the vegetable mixture up to 2 days ahead. Assemble the casserole (without baking), cover tightly, and refrigerate. Bake when ready to serve.
Frequently Asked Questions
Can I use all zucchini or all yellow squash?
Yes, either one works great. Using both adds color, but feel free to use what you have.
Is this dish spicy?
It depends on the salsa and green chiles you use. For a mild version, choose a mild salsa and skip the green chiles.
Can I make it dairy-free?
Yes. Use dairy-free cheese and sour cream alternatives, or omit them entirely and add a drizzle of olive oil or avocado after baking.
Can I use canned corn?
Yes. Drain it well before adding. Fresh or frozen corn will have better texture, but canned works in a pinch.
Do I need to cook the squash fully before baking?
No. You want the squash to be partially tender after sautéing — it will finish softening in the oven without turning mushy.
Final Thoughts
This Mexican Squash Casserole is proof that fresh, healthy ingredients can become something incredibly comforting when paired with the right spices, a little cheese, and some oven time. It’s hearty enough to satisfy, yet filled with wholesome vegetables and plant-based protein. Plus, it’s flexible enough to adapt to your dietary needs, your spice preferences, or whatever you have in your fridge.
Whether you’re serving this as a meatless main or a crowd-pleasing side, it’s a recipe that always hits the spot — warm, cheesy, and full of southwest flavor. Make it once, and it just might become a seasonal favorite in your household.
