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If you ask me, casseroles are the best way to sneak extra veggies onto the dinner table.
This Mediterranean-inspired dish combines tender zucchini and fresh spinach with creamy feta cheese for a satisfying vegetarian main course. The layers of vegetables meld together with herbs and a light coating of breadcrumbs on top.
It’s baked until golden brown, with the feta cheese adding just the right amount of saltiness throughout. The zucchini stays firm enough to hold its shape while the spinach wilts down perfectly between the layers.
It’s a family-friendly meal that’s filling but not heavy, perfect for those nights when you want something warm and comforting.
Why You’ll Love This Zucchini Spinach Casserole
- Health-conscious ingredients – Made with low-fat cheese, egg whites, and loads of vegetables, this casserole fits perfectly into a healthy eating plan while still tasting great.
- Quick prep time – You can have this dish ready for the oven in just 15 minutes, making it perfect for busy weeknight dinners.
- Budget-friendly – Using simple, seasonal vegetables and basic pantry ingredients, this casserole is easy on your wallet while being full of nutrition.
- Vegetarian-friendly – This meatless dish is perfect for vegetarians or anyone looking to add more plant-based meals to their routine.
- Meal prep friendly – You can prepare this casserole ahead of time and reheat portions throughout the week for easy lunches or dinners.
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 usually more tender and have smaller seeds than larger ones. If you spot zucchini that’s bigger than 12 inches at the store, it’s best to skip it – these jumbo ones tend to be watery and have tough seeds that can make your casserole soggy. When picking your zucchini, look for ones that feel firm and heavy for their size, with smooth, bright green skin. You don’t need to peel them either – just give them a good wash, trim the ends, and you’re ready to dice them up for your casserole.
Options for Substitutions
This healthy casserole is pretty adaptable and works well with several substitutions:
- Spinach: Fresh spinach can be swapped with frozen spinach (thawed and well-drained) or other leafy greens like Swiss chard or kale. If using kale, cook it a bit longer to make sure it’s tender.
- Zucchini and yellow squash: You can use all zucchini or all yellow squash, or try other summer squash varieties. Just make sure to dice them finely for even cooking.
- Feta cheese: If you’re not a feta fan, try using crumbled goat cheese or ricotta. For a dairy-free version, try firm tofu crumbles seasoned with a bit of extra salt.
- Whole wheat panko: Regular panko works fine, or try crushed whole wheat crackers, breadcrumbs, or even crushed almonds for a low-carb option.
- Egg whites: You can use one whole egg instead of two egg whites, or for a vegan version, try 2 tablespoons of ground flax mixed with 6 tablespoons of water (let it sit for 5 minutes before using).
- Dried basil: Fresh basil works great (use 1 tablespoon chopped), or swap with dried oregano or Italian seasoning blend.
Watch Out for These Mistakes While Cooking
The biggest challenge when making this zucchini casserole is dealing with excess moisture – failing to remove water from both the spinach and zucchini can lead to a soupy, rather than creamy, final dish. To prevent this, make sure to thoroughly squeeze the spinach dry after cooking and salt the diced zucchini, letting it sit for 15 minutes before patting it dry with paper towels. Another common mistake is undercooking the vegetables before assembling the casserole – take time to properly sauté them until they release their moisture and begin to brown slightly, which adds more flavor and better texture. For the crispiest top layer, avoid stirring the panko-cheese mixture into the vegetables – instead, spread it evenly on top and broil for the final 2-3 minutes of cooking time, watching carefully to prevent burning.
What to Serve With Zucchini Spinach Casserole?
This light and veggie-packed casserole pairs wonderfully with a variety of sides to make it a complete meal. For a simple weeknight dinner, serve it alongside some grilled chicken breast or baked salmon to add protein. If you’re keeping things vegetarian, try it with quinoa or brown rice to soak up all the tasty cheese and veggie flavors. I also like serving this with a slice of crusty whole grain bread or even some roasted cherry tomatoes on the side for extra Mediterranean flair.
Storage Instructions
Keep Fresh: This tasty casserole will stay good in the fridge for up to 4 days when stored in an airtight container. The flavors actually get better after a day as everything melds together! It’s perfect for meal prep and makes great leftovers for quick lunches.
Freeze: You can freeze portions of this casserole for up to 3 months. Just wrap it well in foil and place in a freezer-safe container. Keep in mind that the zucchini might release a bit more water when thawed, but it’s still perfectly good to eat!
Reheat: To warm up your casserole, pop it in the microwave for 1-2 minutes or heat it in the oven at 350°F for about 15-20 minutes until heated through. If it seems a bit watery after reheating, you can drain off any excess liquid that may have released from the vegetables.
| Preparation Time | 10-15 minutes |
| Cooking Time | 30-40 minutes |
| Total Time | 40-55 minutes |
| Level of Difficulty | Easy |
Estimated Nutrition
Estimated nutrition for the whole recipe (without optional ingredients):
- Calories: 350-400
- Protein: 20-25 g
- Fat: 20-25 g
- Carbohydrates: 30-35 g
Ingredients
- 2 tablespoons olive oil
- 3 cups tender spinach leaves
- 2 small zucchini, diced finely
- 2 small yellow squash, diced finely (or substitute with 2 more zucchini if unavailable)
- 1/4 cup crumbled feta cheese (fat-free)
- 1/4 cup grated parmesan cheese (low-fat)
- 1/4 cup whole wheat panko crumbs
- 2 egg whites
- 1/2 teaspoon kosher salt
- 2 teaspoons garlic powder
- 1/2 teaspoon black pepper, ground
- 1 teaspoon dried basil leaves
Step 1: Prepare the Oven and Casserole Dish
Preheat your oven to 400°F (200°C).
Take a 9 x 13 inch casserole dish and spray it thoroughly with non-stick spray to prevent the casserole from sticking during baking.
Set the dish aside while you prepare the rest of the ingredients.
Step 2: Cook the Vegetables
In a large skillet, heat a bit of olive oil over medium heat.
Once the oil is hot, add the spinach, zucchini, and yellow squash.
Stir and cook for about 5 minutes, or until the spinach is fully wilted and the squash is soft.
Be sure to occasionally stir to evenly cook all the veggies.
Once cooked, drain off any excess liquid to avoid a soupy casserole.
Step 3: Combine Ingredients
Transfer the cooked veggie mixture to a large mixing bowl.
Add the remaining ingredients of your choice to the bowl with the spinach mixture.
Stir well to ensure everything is evenly combined.
This forms the base of your casserole, so make sure all the flavors are well mixed.
Step 4: Assemble and Bake the Casserole
Spread the combined mixture in an even layer in your prepared casserole dish.
Place the dish in the preheated oven and bake for 30 to 40 minutes, or until the top is golden brown and the casserole is set.
Step 5: Let Cool and Serve
After baking, remove the casserole from the oven and let it cool slightly.
This cooling period helps the flavors settle and makes serving easier.
Once slightly cooled, slice the casserole into portions and serve.
Enjoy your delicious, veggie-packed casserole!