Name: Zucchini Dill Casserole Recipe
Prep time: 25 min
Cook time: 40 min
Total time: 65 min
Ingredients: 4 medium zucchini, thinly sliced; 1 small yellow onion, finely diced; 2 cloves garlic, minced; 2 tablespoons fresh dill, finely chopped; 2 tablespoons green onions, thinly sliced; 1 1/2 cups shredded mozzarella cheese; 1/2 cup grated Parmesan cheese; 1 cup sour cream; 1/2 cup plain Greek yogurt or sour cream; 3 large eggs; 3/4 cup panko breadcrumbs; 2 tablespoons olive oil or melted butter; 1 teaspoon kosher salt, plus more to taste; 1/2 teaspoon black pepper; 1/2 teaspoon onion powder; 1/2 teaspoon garlic powder; 1/4 teaspoon paprika; 2 tablespoons milk or water, if needed to loosen mixture; 1 teaspoon olive oil or butter, for greasing the baking dish

Zucchini Dill Casserole Recipe tastes creamy, fresh, and herby with a golden cheesy top that feels like summer comfort food. It works perfectly for busy weeknights or relaxed weekend brunch and takes about 1 hour from start to finish. I tested this version so many times that my family started calling it “the green lasagna that smells like a garden.”

Why You Should Try This Zucchini Dill Casserole Recipe

This Zucchini Dill Casserole Recipe packs in a ton of vegetables while still tasting like comfort food. The fresh dill and garlic keep the flavor bright, and the cheese and eggs give it a cozy, almost quiche-like texture.

You can serve it as a vegetarian main or as a side with simple grilled chicken or fish. It also works well for meal prep, since the flavors deepen in the fridge and reheat nicely.

“This Zucchini Dill Casserole Recipe tastes like summer in a baking dish and somehow disappears every time I set it on the table. ★★★★★”

Ingredients You’ll Need

I list everything for a standard 9×13 inch baking dish. You can halve the recipe for an 8×8 pan and slightly reduce the baking time.

Vegetables

4 medium zucchini, thinly sliced (about 2 to 2 ½ pounds; smaller zucchini taste sweeter and less watery)
1 small yellow onion, finely diced
2 cloves garlic, minced (jarred minced garlic works in a pinch)
2 tablespoons fresh dill, finely chopped (or 2 teaspoons dried dill if you cannot find fresh)
2 green onions, thinly sliced (optional, for extra onion flavor and color)

Dairy & Eggs

1 ½ cups shredded mozzarella cheese (low moisture, part skim melts nicely and browns well)
½ cup grated Parmesan cheese (use real Parmigiano Reggiano or a good domestic brand, not the green can if you can help it)
1 cup sour cream (full fat tastes richer, light sour cream still works)
½ cup plain Greek yogurt or more sour cream (Greek yogurt adds a little tang and protein)
3 large eggs

Dry Ingredients & Seasoning

¾ cup panko breadcrumbs (or regular breadcrumbs; use gluten free crumbs if needed)
2 tablespoons olive oil (or melted butter)
1 teaspoon kosher salt, plus more to taste
½ teaspoon black pepper
½ teaspoon onion powder
½ teaspoon garlic powder
¼ teaspoon paprika (smoked or sweet, your choice)

Pantry Shortcuts & Substitutions

Use pre-shredded cheese if you need speed, though fresh grated cheese melts smoother.
Swap Greek yogurt with extra sour cream if you do not keep yogurt around.
Replace mozzarella with Monterey Jack or a mild cheddar if that is what you have.
Use dried dill when fresh dill costs too much or looks sad in the store; just reduce the amount since dried dill tastes stronger.

Equipment List

9×13 inch baking dish
Large skillet or sauté pan
Large mixing bowl
Small bowl for topping
Sharp knife and cutting board
Box grater (if shredding cheese)
Whisk or fork
Clean kitchen towel or paper towels for drying zucchini
Aluminum foil

Tips & Tricks

Salt the zucchini slices lightly and let them sit 10 to 15 minutes, then pat them dry so the casserole does not turn watery.
Slice the zucchini evenly so they cook at the same rate and keep a nice texture.
Use fresh dill when you can, since it gives the casserole a bright, almost lemony flavor.
Mix the eggs with the dairy completely so you avoid streaky or scrambled bits in the casserole.
Add a little extra cheese on top in the last 10 minutes if you want a deeper golden crust.
Let the casserole rest 10 to 15 minutes before slicing so it sets and cuts cleanly.
Taste the mixture before baking and adjust salt and pepper, since bland zucchini needs a flavor boost.
Line the baking dish with a thin swipe of oil or butter so nothing sticks and cleanup stays easy.

How to Make Zucchini Dill Casserole Recipe

Step 1: Prep the Zucchini

Preheat your oven to 375°F and lightly grease a 9×13 inch baking dish with olive oil or butter. Slice the zucchini into thin rounds, about ⅛ to ¼ inch thick, so they soften nicely but still hold shape. Spread the slices on a large tray, sprinkle with a little salt, and let them sit 10 to 15 minutes so they release extra moisture.

After they sit, pat both sides of the zucchini dry with a clean towel or paper towels. This step keeps the Zucchini Dill Casserole Recipe from turning soupy and helps the flavors stay concentrated. Set the zucchini aside while you prepare the rest.

Step 2: Sauté the Aromatics

Heat a tablespoon of olive oil in a large skillet over medium heat. Add the diced onion and cook until it turns soft and lightly golden, about 5 to 7 minutes, while you stir occasionally. Add the minced garlic and cook 30 to 60 seconds until it smells fragrant, not burnt.

Turn off the heat and stir in the chopped fresh dill and green onions. The residual heat softens the herbs and releases their flavor. Let the mixture cool slightly so it does not scramble the eggs later.

Step 3: Mix the Creamy Base

In a large mixing bowl, whisk the eggs until they look smooth and slightly frothy. Add sour cream, Greek yogurt, salt, pepper, onion powder, garlic powder, and paprika. Whisk until the mixture turns smooth and creamy.

Stir in the mozzarella and Parmesan cheese. Fold in the sautéed onion, garlic, and dill mixture. Taste a tiny bit and adjust salt and pepper so the base tastes well seasoned before you add the zucchini.

Step 4: Combine Zucchini with the Filling

Add the dried zucchini slices to the bowl with the creamy egg mixture. Gently fold everything together so every slice gets coated. Take your time and avoid breaking up the zucchini too much.

If the mixture looks very thick, add 1 to 2 tablespoons of milk or water to loosen it slightly. You want a thick but pourable consistency that still clings to the vegetables. Once it looks even, you can move on to assembling the casserole.

Step 5: Assemble in the Baking Dish

Pour the zucchini mixture into the prepared baking dish and spread it into an even layer. Tuck any stray zucchini slices under the surface so they do not dry out. Smooth the top with a spatula so it bakes evenly.

In a small bowl, mix the panko breadcrumbs with olive oil or melted butter and a pinch of salt and pepper. Sprinkle this mixture evenly over the top of the casserole. The crumbs will bake into a crunchy, golden crust that contrasts with the soft zucchini.

Step 6: Bake the Casserole

Cover the baking dish loosely with foil so the top does not brown too quickly. Bake at 375°F for about 25 minutes. The casserole should look mostly set around the edges at this point.

Remove the foil and bake another 15 to 20 minutes until the top turns golden and the center feels set when you jiggle the dish. If you want deeper color, move the dish to the top rack for the last 5 minutes. The casserole should reach at least 165°F in the center if you check with a thermometer.

Step 7: Rest and Serve

Take the Zucchini Dill Casserole Recipe out of the oven and set the dish on a cooling rack. Let it rest 10 to 15 minutes so the eggs firm up and the slices hold shape. This short wait also gives the flavors a chance to settle and blend.

Slice into squares and use a spatula to lift them out. Sprinkle a little extra fresh dill or green onion on top if you want a fresh pop of color. Serve warm and enjoy the creamy, herby layers.

What to Serve with Zucchini Dill Casserole Recipe

This Zucchini Dill Casserole Recipe pairs nicely with simple grilled or baked chicken, turkey meatballs, or a piece of salmon for a balanced dinner. You can also serve it with a crisp green salad, sliced tomatoes with olive oil and salt, or roasted carrots. If you want a brunch spread, add scrambled eggs, fresh fruit, and toast or English muffins. Offer iced tea, sparkling water with lemon, or a light lemonade to keep the meal bright and refreshing.

Storage Options

Cool leftovers to room temperature, then cover the dish tightly or transfer slices to airtight containers and store in the fridge for up to 4 days.
Reheat single portions in the microwave in 30 second bursts until hot, or warm larger portions in a 325°F oven for 15 to 20 minutes so the top stays a bit crisp.
Freeze individual slices on a parchment lined tray until firm, then wrap them and store in a freezer bag for up to 2 months.
Reheat frozen slices in a covered dish at 350°F for about 25 to 30 minutes, then uncover for the last few minutes so the breadcrumb topping crisps again.