Savory Zucchini Quinoa Casserole

As someone who’s always trying to eat a bit healthier, I’m constantly on the lookout for ways to sneak more vegetables into our family meals. This zucchini quinoa casserole has become a regular at our dinner table, and for good reason. It’s one of those dishes that just feels good to make and even better to eat.

I usually prep this casserole while I’m making lunch, chopping extra zucchini and cooking a bigger batch of quinoa than I need. That way, when dinner rolls around, I’m already halfway there. My kids, who normally give zucchini the side-eye, actually ask for seconds when I serve this. Maybe it’s the melty cheese on top, or maybe they’re finally coming around to vegetables – either way, I’m not questioning it!

The best part? This casserole is perfect for busy weeknights, and any leftovers make a great lunch the next day. It’s simple, satisfying, and the kind of meal that makes you feel like you’ve got this whole healthy eating thing figured out – at least for today.

What Kind of Zucchini Should I Use?

For this casserole, medium-sized zucchini (about 6-8 inches long) are your best bet since they’re tender and have smaller seeds than larger ones. If you spot giant zucchini at the market, it’s best to skip those – they tend to be watery and have tough, bitter seeds that can affect your dish. When shopping, look for zucchini that feels firm and heavy for its size, with smooth, blemish-free dark green skin. A good tip is to give them a gentle squeeze – if they feel spongy, keep looking, as fresh zucchini should be nice and firm.

Options for Substitutions

This casserole is pretty flexible and allows for several ingredient swaps if needed:

• Quinoa: You can swap quinoa with cooked brown rice, cauliflower rice (for low-carb), or even cooked barley. Just make sure whatever grain you use is well-drained to avoid a soggy casserole.
• Zucchini and yellow squash: Feel free to use all zucchini or all yellow squash if you can’t find both. You could also mix in some eggplant or bell peppers – just make sure to keep the total amount of vegetables the same.
• White Cheddar/Monterey Jack: Any melting cheese works well here – try regular cheddar, mozzarella, or even pepper jack for a spicier kick.
• Sour cream: Plain Greek yogurt makes a great substitute for sour cream and adds extra protein. Just make sure to use full-fat yogurt for the best texture.
• Panko: Regular breadcrumbs work fine, or try crushed crackers, crushed corn flakes, or even crushed pork rinds for a low-carb option.
• Green chiles: If you can’t find canned green chiles, you can use fresh diced jalapeños (remove seeds for less heat) or even a can of diced mild green peppers.

Watch Out for These Mistakes While Cooking

The biggest challenge when making zucchini quinoa casserole is dealing with excess moisture – make sure to salt your sliced zucchini and yellow squash, let them sit for 15-20 minutes, then pat them dry with paper towels to prevent a watery casserole. Another common mistake is undercooking the quinoa before adding it to the casserole – it should be fully cooked and fluffy, as it won’t cook much more in the oven. When layering your ingredients, avoid dumping everything in at once; instead, create even layers and make sure the panko topping is distributed uniformly for that perfect crispy crust. For the best texture, let the casserole rest for 10-15 minutes after baking, which allows it to set properly and makes it easier to serve in neat portions.

What to Serve With Zucchini Quinoa Casserole?

This hearty casserole works great as a main dish, but you might want some simple sides to round out your meal. A fresh green salad with cherry tomatoes and a light vinaigrette makes a perfect partner, cutting through the richness of the cheese and mayo. If you’re serving this for dinner, try adding some grilled chicken or roasted salmon on the side for extra protein. For a complete vegetarian spread, I like to serve it with some crusty whole grain bread and roasted Brussels sprouts or steamed broccoli – the slightly bitter vegetables balance out the creamy casserole really nicely.

Storage Instructions

Keep Fresh: This zucchini quinoa casserole is perfect for leftovers! Place any remaining portions in an airtight container and pop it in the fridge – it’ll stay good for up to 4 days. The flavors actually get even better after a day as everything melds together.

Freeze: Want to save some for later? Let the casserole cool completely, then wrap portions tightly in foil and place in freezer bags. It’ll keep well in the freezer for up to 3 months. Just remember that the zucchini might be a bit softer when thawed.

Reheat: To warm up your casserole, cover it with foil and pop it in the oven at 350°F for about 20-25 minutes, or until heated through. For single servings, the microwave works great too – just heat in 1-minute intervals, stirring between each, until it’s nice and hot.

Make Ahead: You can prep this casserole a day ahead! Just assemble everything except the panko topping, cover, and refrigerate. When you’re ready to bake, add the panko and cheese topping, and add an extra 10-15 minutes to the baking time since it’ll be cold from the fridge.

Preparation Time	15-20 minutes
Cooking Time	45-50 minutes
Total Time	60-70 minutes
Level of Difficulty	Medium

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 2900-3200
• Protein: 85-100 g
• Fat: 180-200 g
• Carbohydrates: 250-270 g

Ingredients

• Nonstick spray or oil for baking dish
• 2 tablespoons canola oil
• 4 tablespoons butter, divided (1/2 stick)
• 1 medium onion, finely chopped
• 1 1/2 pounds zucchini, cut into 1/4-inch slices
• 1 1/2 pounds yellow squash, cut into 1/4-inch slices
• 4 cloves garlic, minced
• Two 4-ounce cans of diced green chiles (hot or mild, drained)
• 3 cups quinoa, cooked
• Salt and pepper to taste
• 2 cups shredded white cheddar or monterey jack
• 3/4 cup sour cream
• 3/4 cup mayonnaise
• 2 large eggs
• 1 cup panko
• 1/2 cup freshly grated parmesan or asiago cheese

Step 1: Prepare Your Baking Dish and Oven

Begin by preheating your oven to 350°F (175°C).

While the oven is heating, prepare a 13 x 9-inch baking dish by spraying it with cooking spray or lightly rubbing it with oil to prevent sticking.

Set the dish aside for later use.

Step 2: Cook the Vegetables

In a large skillet or sauté pan, heat some oil along with 2 tablespoons of butter over medium-high heat.

Add the onion to the pan, reduce the heat to medium, and cook for 5-6 minutes until the onions begin to soften.

Add the zucchini and yellow squash, continuing to cook over medium heat for another 5-6 minutes until they start to soften.

Add garlic and cook for about 15 seconds until fragrant.

Remove from heat and let the vegetable mixture cool.

Step 3: Combine Vegetables with Quinoa and Cheese

Once the vegetables have cooled, transfer them to a large bowl.

Add in the green chiles, quinoa, and your choice of Cheddar or Monterey Jack cheese.

Season the mixture to taste with salt and black pepper, ensuring everything is well combined.

Step 4: Prepare the Creamy Mixture

In a separate small bowl, combine the sour cream, mayonnaise, and eggs.

Mix well until smooth.

Add this creamy mixture to the bowl with the vegetables, quinoa, and cheese.

Stir everything together until it’s evenly incorporated.

Step 5: Assemble the Casserole

Transfer the combined mixture into the prepared 13 x 9-inch baking dish, spreading it out evenly.

In a small bowl, combine the remaining butter, panko breadcrumbs, and your choice of Parmesan or Asiago cheese.

Sprinkle this breadcrumb mixture evenly over the top of the casserole.

Step 6: Bake and Serve

Place the baking dish in the preheated oven and bake uncovered for 45-50 minutes, or until the top is golden brown and the casserole is set.

Once done, remove from the oven and let it cool slightly before serving.

Enjoy your flavorful and satisfying casserole!