Simple Zucchini Dill Casserole

Zucchini casseroles have become my go-to way to use up all that summer zucchini from our garden. There’s something so satisfying about turning those giant zucchinis into a warm, comforting dish that even my kids will eat.

This version with fresh dill brings such a nice, bright flavor that pairs perfectly with the tender zucchini and creamy cheese.

It’s one of those simple, wholesome recipes that comes together easily on busy weeknights and makes the whole house smell amazing!

The Best Zucchini for Your Recipe

For this casserole, medium-sized zucchini (about 7-8 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 a foot long at the store, it’s best to skip those – they tend to be watery and have tough, bitter seeds that can affect your casserole’s texture.

When picking your zucchini, look for ones that feel firm and heavy for their size, with smooth, blemish-free dark green skin.

A good tip is to avoid peeling your zucchini before dicing it – the skin adds nice color and extra nutrients to your dish.

Helpful Ingredient Alternatives

This casserole is pretty adaptable and here are some helpful swaps you can try:

• Baking mix: If you don’t have baking mix on hand, you can make your own by combining 1 cup all-purpose flour with 1½ teaspoons baking powder and ¼ teaspoon salt. You can also use gluten-free baking mix for a gluten-free version.
• Parmesan cheese: Romano cheese works great as a substitute, or try Pecorino for a sharper taste. If you’re out of hard Italian cheese, sharp cheddar can work too, though it will change the flavor profile a bit.
• Dried dill: Fresh dill works well too – just use 3 tablespoons since fresh herbs are less concentrated. You could also try dried basil or thyme if you’re not a fan of dill.
• Canola oil: Any neutral-flavored oil like vegetable oil or light olive oil will work just fine. You can even use melted butter for a richer taste.
• Zucchini: Yellow summer squash makes a perfect substitute, or try a mix of both. Just make sure to remove excess moisture from whatever squash you use by patting it dry after dicing.

Best Storage Practices

Keep Fresh: This zucchini dill casserole stays good in the fridge for up to 4 days when kept in an airtight container. It’s one of those dishes that actually tastes great the next day, as the flavors have time to meld together even more!

Freeze: You can freeze portions of this casserole for up to 3 months. Just wrap it well in foil and place it 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 oven at 350°F for about 15-20 minutes, or until heated through. If you’re in a hurry, the microwave works too – just heat in 30-second intervals, though the texture might not be quite as nice as the oven method.

Make Ahead: You can prep this casserole a day ahead! Just assemble everything, cover with foil, and keep it in the fridge overnight. When you’re ready, let it sit at room temperature for 30 minutes before baking according to the recipe.

Preparation Time	10-15 minutes
Cooking Time	25-30 minutes
Total Time	35-45 minutes
Level of Difficulty	Easy

Estimated Nutrition

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

• Calories: 1400-1600
• Protein: 40-50 g
• Fat: 100-110 g
• Carbohydrates: 80-90 g

Ingredients

• 1 tbsp dried dill (or 3 tbsp fresh dill, finely chopped)
• 1/2 cup canola oil (or any neutral oil)
• 1 cup biscuit mix (I use Bisquick)
• 4 large eggs (room temperature)
• 1/8 tsp black pepper
• 3 cups diced zucchini (cut into 1/4-inch cubes)
• 1 tsp salt
• 1 large onion (diced into 1/2-inch pieces)
• 1/2 cup shredded Parmesan cheese (freshly grated preferred for better flavor)

Step 1: Prepare Your Mise en Place and Preheat

• 3 cups zucchini, diced
• 1 large onion, diced
• 1 tbsp fresh dill

Start by preheating your oven to 375°F and lightly greasing a 9×13-inch baking dish with oil or cooking spray.

While the oven preheats, dice your zucchini into 1/4-inch cubes and dice your onion into 1/2-inch pieces.

Set these aside in separate bowls.

If using fresh dill instead of dried, finely chop it now.

Having everything prepped and ready before you start mixing will ensure you work efficiently and the vegetables maintain their texture.

I like to cut the zucchini smaller than the onion so it cooks evenly throughout the casserole.

Step 2: Build the Batter Base

• 1 cup biscuit mix
• 1/2 cup shredded Parmesan cheese
• 1 tbsp dried dill
• 1 tsp salt
• 1/8 tsp black pepper

In a large mixing bowl, combine the biscuit mix, freshly grated Parmesan cheese, dried dill, salt, and black pepper.

Whisk these dry ingredients together thoroughly to distribute the seasonings evenly throughout.

I find that freshly grated Parmesan melts more smoothly into the batter than pre-shredded varieties, which often contain anti-caking agents.

This dry mixture forms the foundation of your casserole, so make sure everything is well combined before moving to the next step.

Step 3: Create the Wet Batter and Combine

• 4 large eggs
• 1/2 cup canola oil

Pour the eggs and canola oil into the dry mixture and stir vigorously until you have a smooth, uniform batter.

The eggs and oil work together to create a rich, moist crumb structure that gives this casserole its tender texture.

Mix for about 30 seconds until no streaks of dry ingredients remain, but don’t overmix as this isn’t a cake batter that requires careful handling.

The consistency should resemble thick pancake batter.

Step 4: Fold in Vegetables and Assemble

• Batter from Step 3
• 3 cups diced zucchini
• 1 large onion, diced

Add the diced zucchini and onion to the batter and fold together gently but thoroughly, using a spatula to combine without breaking down the vegetables.

The zucchini will release moisture as it cooks, so don’t worry if the batter seems a bit wet—this is exactly what you want.

Pour the entire mixture into your prepared baking dish and smooth the top with a spatula so it bakes evenly.

I like to let it sit in the dish for just a minute before baking to allow the biscuit mix to absorb some moisture, which helps it rise properly in the oven.

Step 5: Bake Until Golden and Set

Bake at 375°F for 25 to 30 minutes, until the top is golden brown and a toothpick inserted into the center comes out clean or with just a few moist crumbs.

The casserole will puff up slightly as it bakes and the edges should pull away from the sides of the dish just a bit.

If the top is browning too quickly before the center is set, you can loosely tent it with foil for the last 5-10 minutes.

Once done, remove from the oven and let it cool for 5 minutes before cutting into squares for serving.