Herb-Crusted Southern Zucchini Casserole

If you ask me, zucchini casseroles are one of the best ways to use up summer’s bounty.

This comforting Southern dish combines fresh garden zucchini with cheese, herbs, and a buttery crumb topping that’ll make anyone come back for seconds. The tender squash mingles with savory seasonings and gets perfectly baked until golden on top.

It’s layered with classic ingredients like sour cream and sharp cheddar, then topped with crispy breadcrumbs that brown beautifully in the oven. Simple pantry staples help turn plain zucchini into something special.

It’s a family-style side dish that feels right at home next to grilled chicken or Sunday roast, perfect for summer gatherings or weeknight dinners.

What Kind of Zucchini Should I Use?

For this casserole, you’ll want to look for small to medium-sized zucchini that are about 6-8 inches long. These younger, smaller zucchini are perfect because they’re more tender and have smaller seeds than their larger counterparts. When shopping, pick zucchini that feel firm and heavy for their size, with smooth, blemish-free dark green skin. If you can only find larger zucchini, they’ll work too – just be sure to remove the seedy center if it’s particularly large, as this can make your casserole watery. For the best results, slice your zucchini into even, medium-thick pieces (about 1/4 inch) so they cook uniformly in the casserole.

Options for Substitutions

This casserole recipe is pretty adaptable and here’s how you can switch things up:

• Yellow squash and zucchini: You can use all zucchini or all yellow squash if you prefer. Pattypan squash works great too. Just keep the total amount of squash the same at 4 cups.
• Mayonnaise: Not a mayo fan? Greek yogurt or sour cream make good substitutes. You might want to reduce the lemon juice if using Greek yogurt since it’s already tangy.
• Chicken broth: Vegetable broth works just as well, or you can use water with a pinch of extra salt and herbs.
• Panko breadcrumbs: Regular breadcrumbs, crushed crackers, or crushed cornflakes all work for the topping. If you’re going low-carb, try crushed pork rinds or extra parmesan cheese.
• Parmesan cheese: Romano or Pecorino cheese can step in for Parmesan. For a different flavor, try shredded Gruyere or sharp cheddar.
• Italian herbs: If you don’t have an Italian herb blend, use any mix of dried basil, oregano, and thyme. Fresh herbs work too – just double the amount.

Watch Out for These Mistakes While Cooking

The biggest challenge when making zucchini casserole is dealing with excess moisture – slicing your squash too thick or not removing excess water can leave you with a soupy mess instead of a creamy casserole. To prevent this, slice your zucchini and yellow squash into uniform 1/4-inch pieces, then lay them on paper towels and sprinkle with salt for 15 minutes to draw out moisture before patting dry. Another common mistake is undercooking the vegetables before adding the topping – you’ll want to bake the casserole until the squash is tender but still holds its shape, usually about 20-25 minutes, before adding the breadcrumb mixture. For the crispiest topping, avoid pressing the breadcrumb mixture down into the casserole – instead, sprinkle it loosely over the top and drizzle with melted butter just before the final few minutes of baking under the broiler.

What to Serve With Zucchini Casserole?

This cheesy zucchini casserole makes a fantastic side dish, but it can also shine as a vegetarian main course with the right accompaniments. For a complete meal, try serving it alongside some grilled chicken or a juicy pork chop – the creamy, garlicky flavors pair really well with most proteins. If you’re keeping things meatless, a simple green salad and some crusty French bread will round out your plate nicely. You can also serve it next to some fluffy rice or quinoa to soak up all that tasty sauce, making sure none of the good stuff goes to waste!

Storage Instructions

Keep Fresh: Your zucchini casserole will stay good in the fridge for up to 4 days when stored in an airtight container. The panko topping might lose some of its crunch over time, but the flavors will continue to develop nicely as it sits.

Make Ahead: You can prep this casserole up to 24 hours in advance! Just assemble everything except the panko topping, cover, and pop it in the fridge. When you’re ready to bake, add the breadcrumb mixture and proceed with the recipe as written. This is super handy for busy weeknights or when company’s coming.

Reheat: To warm up leftovers, pop them in the oven at 350°F for about 15-20 minutes until heated through. If you’re in a hurry, the microwave works too – just know the topping won’t be as crispy. A quick tip: sprinkle a few fresh breadcrumbs on top before reheating to bring back some of that crunch!

Preparation Time	15-20 minutes
Cooking Time	35-40 minutes
Total Time	50-60 minutes
Level of Difficulty	Easy

Estimated Nutrition

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

• Calories: 800-900
• Protein: 15-20 g
• Fat: 60-70 g
• Carbohydrates: 50-60 g

Ingredients

• 2 cups sliced yellow squash (approximately 2 small ones)
• 2 cups sliced zucchini (approximately 2 small ones)
• 1/2 cup mayonnaise
• 2 tablespoons chicken broth
• 1 teaspoon lemon juice
• 1 teaspoon salt
• 1/2 teaspoon minced garlic
• 1/2 teaspoon coarse ground black pepper
• 1/4 cup grated parmesan cheese
• 1/4 cup panko breadcrumbs
• 2 teaspoons italian herbs
• 2 tablespoons melted butter

Step 1: Prepare the Baking Dish and Preheat Oven

Preheat your oven to 350° Fahrenheit.

Meanwhile, generously butter a 2-quart baking dish or a small cast iron skillet.

This will prevent the squash from sticking and add a rich flavor to the dish.

Step 2: Make the Mayo Broth Mixture

In a large measuring cup, whisk together mayonnaise, broth, lemon juice, salt, pepper, and garlic.

Mix thoroughly until well combined.

Set this mixture aside; it will serve as the flavorful base for your squash bake.

Step 3: Prepare and Coat the Squash

Slice both squashes into approximately 1/4-inch slices to ensure they become crisp-tender when baked.

Place the sliced squash into a large mixing bowl.

Pour the prepared mayo/broth mixture over the squash and toss until all slices are well coated.

Transfer the coated squash into the buttered baking dish, arranging them as evenly as possible.

Pour any leftover sauce over the squash in the dish.

Step 4: Prepare and Add the Topping

In a small bowl, use a fork to mix together panko, Parmesan, and Italian seasoning.

This will create a flavorful, crunchy topping for the squash.

Evenly sprinkle this topping over the coated squash in the baking dish.

You may use all or a portion of the topping, depending on your preference.

Step 5: Bake and Broil the Squash

Cover the baking dish with foil and place it in the preheated oven.

Bake for 30 minutes to allow the squash to soften and absorb the flavors.

After baking, remove the foil and change the oven setting to broil.

Place the dish back in the oven and broil for 5-7 minutes to achieve a beautifully browned and crispy topping.

Keep a close eye to prevent burning.

Step 6: Serve and Enjoy

After the topping is browned to your liking, carefully remove the dish from the oven.

Let it cool slightly before serving.

Enjoy this delicious and flavorful squash bake as a side dish or a light main course.