Panko Crusted Zucchini Quinoa Casserole

Here’s my go-to zucchini quinoa casserole recipe, combining protein-rich quinoa with fresh garden zucchini, melted cheese, and just the right blend of herbs and seasonings.

This casserole has become my weeknight dinner hero – it’s one of those dishes that even the kids ask for seconds. I often make a double batch because the leftovers are perfect for lunch the next day. Who doesn’t love having dinner already figured out?

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 zucchini that are bigger than 12 inches at the store, it’s best to skip them – they tend to be woody and have large, bitter seeds that can affect the taste of your dish. When picking zucchini, look for ones that feel firm and heavy for their size, with smooth, unblemished dark green skin. To prep them for the casserole, there’s no need to peel the skin off – just wash them well and trim the ends before cutting into even pieces.

Options for Substitutions

This casserole is pretty flexible and you can make several swaps based on what you have in your kitchen:

• Quinoa: You can swap quinoa with cooked brown rice, bulgur, or even cauliflower rice for a low-carb option. 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 diced 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 avoid non-fat versions as they might make the dish watery.
• Panko breadcrumbs: Regular breadcrumbs work fine, or try crushed crackers, crushed corn flakes, or even ground nuts for a gluten-free option.
• Green chiles: If you can’t find canned green chiles, use fresh diced jalapeños (remove seeds for less heat) or just leave them out if you prefer a mild dish.

Watch Out for These Mistakes While Baking

The biggest challenge when making zucchini quinoa casserole is dealing with excess moisture – make sure to salt your zucchini and yellow squash pieces, let them sit for 15-20 minutes, then pat them thoroughly dry with paper towels to prevent a watery casserole. Another common mistake is undercooking the quinoa – it should be fully cooked and fluffy before adding it to your casserole, as it won’t cook much more in the oven. When preparing the breadcrumb topping, avoid pressing it down too firmly onto the casserole, as this can create a dense, heavy crust instead of the desired crispy texture – simply sprinkle it evenly over the top and drizzle with the remaining melted butter. For the best results, let your casserole rest for 10-15 minutes after baking to help the layers set properly, making it easier to serve and ensuring each portion holds its shape.

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 dressing makes a perfect companion, adding a nice crisp contrast to the creamy casserole. If you’re serving this for dinner, some crusty garlic bread or warm dinner rolls on the side help soak up all the tasty sauce. For a protein boost, you could add some grilled chicken breast or roasted chickpeas on the side – both options pair really nicely with the Mexican-inspired flavors from the green chiles and cheese in this dish.

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 better as they meld together, making it a great make-ahead meal for busy weeknights.

Freeze: Want to save some for later? Let the casserole cool completely, then portion it into freezer-safe containers. It’ll keep well in the freezer for up to 3 months. Just remember that zucchini can release a bit of water when thawed, but it’s still totally yummy!

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 in between. The panko topping might not be as crispy after reheating, but you can run it under the broiler for a minute to crisp it back up.

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: 2600-2800
• Protein: 90-100 g
• Fat: 180-200 g
• Carbohydrates: 200-220 g

Ingredients

• Cooking spray (or oil for greasing the baking dish)
• 2 tablespoons of canola oil
• 4 tablespoons butter (divided, equivalent to half a stick)
• 1 medium onion (finely chopped)
• 1 1/2 pounds zucchini (cut into 1/4-inch pieces)
• 1 1/2 pounds yellow squash (cut into 1/4-inch pieces)
• 4 cloves of garlic (finely minced)
• 2 cans diced green chiles (4 ounces each, hot or mild, drained)
• 3 cups cooked quinoa
• Salt and ground black pepper (to taste)
• 2 cups shredded white cheddar or monterey jack cheese
• 3/4 cup sour cream
• 3/4 cup mayonnaise
• 2 large eggs
• 1 cup panko breadcrumbs
• 1/2 cup grated parmesan or asiago cheese

Step 1: Prepare the Baking Dish and Oven

Preheat your oven to 350 degrees Fahrenheit.

Prepare a 13 x 9-inch baking dish by spraying it with cooking spray or rubbing it lightly with oil to prevent sticking.

Set the baking dish aside as you prepare the other ingredients.

Step 2: Cook the Vegetables

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

Add the onions to the pan, then reduce the heat to medium.

Cook the onions for about 5-6 minutes, stirring occasionally, until they begin to soften.

Add the diced zucchini and yellow squash to the skillet and continue cooking for another 5-6 minutes, or until they begin to soften as well.

Add garlic and stir for about 15 seconds until fragrant.

After cooking, remove the pan from heat and let the vegetables cool slightly.

Step 3: Mix the Filling

In a large bowl, combine the cooled vegetables with green chiles, cooked quinoa, and your choice of either Cheddar or Monterey Jack cheese.

Season the mixture to taste with salt and black pepper to ensure your dish is flavorful.

Step 4: Prepare the Creamy Mixture and Combine

In a small bowl, mix together the sour cream, mayonnaise, and eggs.

Stir this creamy mixture into the vegetable, quinoa, and cheese mixture until everything is evenly combined.

Transfer this combined mixture into the previously prepared baking dish, spreading it out evenly.

Step 5: Prepare the Breadcrumb Topping

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

Mix these ingredients together until well combined.

Evenly sprinkle this breadcrumb mixture over the top of your dish, creating a crispy, golden topping.

Step 6: Bake and Serve

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

Once baked, remove the dish from the oven and allow it to cool slightly.

Slice, serve, and enjoy your flavorful vegetable quinoa bake!