Zucchini Dill Casserole Recipe

Zucchini Dill Casserole Recipe tastes creamy, fresh, and herby with a golden, cheesy top and tender veggies underneath. It works perfectly for busy weeknights or holiday potlucks and takes about 1 hour from start to finish. I first baked this on a sweltering July evening in my tiny apartment kitchen, and my neighbors still ask about “that zucchini thing with the dill.”

Why You Should Try This Zucchini Dill Casserole Recipe

This zucchini dill casserole recipe turns simple summer squash into a cozy, comforting side that can easily pass as a main dish. Fresh dill, garlic, and a touch of lemon keep it bright, while the creamy filling and cheese satisfy that comfort food craving.

You can prep it ahead, stash it in the fridge, and bake it when guests arrive. It also uses budget friendly pantry staples like dried breadcrumbs and shredded cheese, so you skip any fancy specialty ingredients.

“This zucchini dill casserole recipe tastes like summer in a baking dish and disappears from the table every single time. ★★★★★”

Ingredients You’ll Need

Fresh produce

• 4 medium zucchini, thinly sliced into half-moons
• 1 small yellow onion, finely diced
• 2 cloves garlic, minced
• 2 tablespoons fresh dill, finely chopped
• 1 tablespoon fresh parsley, finely chopped (optional but adds color)
• Zest of 1 lemon

You can use yellow squash for half of the zucchini if you need to clean out the fridge. I often mix both for color.

Dairy and eggs

• 1 cup whole milk Greek yogurt or sour cream
• 1 cup shredded mozzarella cheese
• 1/2 cup shredded sharp cheddar or Monterey Jack
• 1/4 cup grated Parmesan cheese
• 2 large eggs

Greek yogurt gives the casserole a tangy, lighter texture. Sour cream works if you want a richer result. Use pre-shredded cheese from a bag on busy nights, but freshly shredded cheese melts more smoothly.

Pantry staples

• 2 tablespoons olive oil or neutral oil
• 2 tablespoons butter
• 3/4 cup plain breadcrumbs (panko or regular)
• 1 teaspoon Dijon mustard
• 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 smoked paprika or sweet paprika
• Pinch of red pepper flakes (optional, for a little heat)

Panko breadcrumbs give a crispier topping. Regular breadcrumbs still work and absorb flavor nicely. You can use seasoned breadcrumbs and reduce the added salt slightly.

Optional add-ins

• 1/2 cup cooked quinoa or rice, for a heartier casserole
• 1/2 cup crumbled feta, for extra tang
• 1/2 cup cooked, crumbled bacon, for a smoky twist

I add feta when I want a more Mediterranean style zucchini dill casserole recipe. Bacon fits when I serve it as a brunch dish.

Equipment list

• 9×13 inch baking dish or similar casserole dish
• Large skillet or sauté pan
• Medium mixing bowl
• Whisk
• Cutting board and sharp knife
• Box grater or food processor with shredding blade
• Measuring cups and spoons

I like a ceramic baking dish because it holds heat well and keeps the casserole warm at the table.

Tips & Tricks

• Salt the sliced zucchini lightly and let it sit 10 to 15 minutes, then pat dry to reduce excess moisture and avoid a watery casserole.
• Slice zucchini evenly, about 1/4 inch thick, so it cooks at the same rate and stays tender, not mushy.
• Use fresh dill for the best flavor and add a little extra on top after baking for a bright, fresh aroma.
• Mix cheeses for better flavor: a mild melter like mozzarella plus a sharper cheese like cheddar or Parmesan.
• Whisk the eggs with yogurt or sour cream until very smooth so the custard bakes evenly without streaks.
• Taste the yogurt mixture before you add eggs and adjust salt, pepper, and dill so the seasoning hits just right.
• Toast breadcrumbs in butter in the skillet for a deeper, nutty flavor and a crisp top that stays crunchy.
• Let the casserole rest 10 minutes after baking so it sets and slices cleanly instead of falling apart.
• Use a baking sheet under the dish if you fill it to the top, so any bubbling cheese lands on the sheet instead of the oven floor.
• Reheat leftovers covered with foil so the top does not burn while the center warms through.

How to Make Zucchini Dill Casserole Recipe

Step 1: Prep and season the zucchini

Wash the zucchini and trim the ends. Slice into 1/4 inch thick half-moons and place them in a large colander set over the sink. Sprinkle with about 1/2 teaspoon salt, toss, and let the zucchini sit 10 to 15 minutes so it releases some water.

After it rests, pat the zucchini dry with clean kitchen towels or paper towels. This step keeps your zucchini dill casserole recipe from turning soupy and helps the flavors concentrate.

Step 2: Sauté veggies and aromatics

Heat 1 tablespoon olive oil and 1 tablespoon butter in a large skillet over medium heat. Add the diced onion and cook, stirring often, until it turns soft and translucent, about 5 to 7 minutes. Add the minced garlic and cook 1 minute, until it smells fragrant.

Add the zucchini to the skillet and toss with the onions and garlic. Cook 5 to 7 minutes, stirring occasionally, until the zucchini starts to soften but still holds its shape. Season with a pinch of salt and pepper, then remove the skillet from the heat and let the veggies cool slightly.

Step 3: Mix the creamy dill filling

In a medium bowl, whisk the eggs until smooth. Add the Greek yogurt or sour cream, Dijon mustard, lemon zest, onion powder, garlic powder, smoked paprika, and red pepper flakes if you use them. Whisk until the mixture turns creamy and uniform.

Stir in the chopped dill and parsley. Fold in the shredded mozzarella, cheddar, and half of the Parmesan. Taste a small spoonful and adjust salt and pepper so the mixture tastes well seasoned.

Step 4: Combine zucchini with the filling

Preheat your oven to 375°F and grease a 9×13 inch baking dish with the remaining tablespoon of olive oil or a little butter. Add the slightly cooled zucchini and onion mixture to the creamy dill filling. Gently fold everything together until the veggies coat evenly with the mixture.

Pour the mixture into the prepared baking dish and spread it into an even layer. Sprinkle the remaining Parmesan over the top.

Step 5: Make the buttery breadcrumb topping

In the same skillet you used for the veggies, melt the remaining 1 tablespoon butter over medium heat. Add the breadcrumbs and stir constantly for 2 to 3 minutes, until they turn light golden and smell toasty. Season with a small pinch of salt and pepper.

Sprinkle the toasted breadcrumbs evenly over the casserole. This topping gives the zucchini dill casserole recipe a crunchy, flavorful crust that contrasts with the creamy interior.

Step 6: Bake the casserole

Place the baking dish on the middle rack of the oven. Bake at 375°F for 25 to 30 minutes, until the casserole bubbles around the edges and the top turns deep golden brown. If the top browns too quickly, tent the dish loosely with foil.

Check the center with a knife; it should feel set, not liquid. Let the casserole rest 10 minutes on a cooling rack so it firms up and slices neatly.

Step 7: Garnish and serve

Sprinkle a little extra fresh dill and parsley over the top right before serving. The herbs wake up the flavors and make the casserole look bright and fresh. Slice into squares and serve warm.

You can serve this zucchini dill casserole recipe as a vegetarian main dish or as a side next to simple proteins. I often pack leftovers for lunch with a crisp salad on the side.

What to Serve with Zucchini Dill Casserole Recipe

This zucchini dill casserole recipe pairs beautifully with a simple green salad tossed with lemony vinaigrette. You can serve it next to grilled chicken, baked salmon, or roasted tofu for a complete meal. Add a side of crusty bread or warm pita to scoop up the creamy filling.

Kids often enjoy it with a side of fresh fruit like watermelon, berries, or sliced apples. A tall glass of iced tea, sparkling water with lemon, or homemade lemonade fits perfectly with the fresh dill and lemon notes.

Storage Options

• Store leftover zucchini dill casserole in an airtight container in the fridge for up to 4 days.
• Cool the casserole completely, then wrap the dish tightly or portion into smaller containers before you refrigerate it.
• Freeze individual portions in freezer safe containers for up to 2 months, and label them with the date.
• Reheat in the oven at 350°F, covered with foil, for 15 to 20 minutes until hot, then uncover for a few minutes to crisp the top again.
• Use the microwave for quick single servings, then finish under the broiler for 1 to 2 minutes to revive the crunchy breadcrumb topping.