Easy Zucchini Casserole for Busy Moms in 15 Minutes

It’s that time of year again, your garden (or local farmer’s market) is bursting with zucchini. They’re everywhere.

You’ve grilled them, spiralized them, baked them into muffins… and now you’re wondering, “What else can I do with all this zucchini?”

Enter: the zucchini casserole recipe that’s taken over kitchens for over a decade. It’s cozy like a quiche, savory like your favorite brunch pie, and shockingly easy to throw together.

Whether you’re feeding your family on a weeknight or making a dish for a potluck, this one’s always a hit.

Why You’ll Love This Zucchini Casserole

If you’re on the hunt for a cozy, crowd-pleasing dish that uses up your surplus of summer zucchini, this zucchini casserole checks every box. It’s one of those recipes that you try once, and then keep making year after year.

This isn’t just a side dish. It’s comfort food with a fresh twist. The texture is quiche-like, fluffy, moist, and tender in the center, with golden, crisp edges.

It has that just-right balance of cheesy goodness and garden-fresh flavor, making it perfect for any meal: brunch, lunch, or dinner.

What makes this casserole a must-make? Let’s break it down:

• It’s incredibly easy to make. Toss everything in a bowl, mix it up, and bake.
• Minimal prep, maximum flavor. No sautéing, no stovetop, no layers—just simple steps with delicious results.
• It’s healthy and satisfying. Made with eggs, olive oil, and fresh vegetables, this dish is protein-packed and rich in nutrients.
• Versatile serving options. Serve it as a brunch bake, a meatless main course, or a vegetable side at dinner.
• Crowd-friendly and potluck-approved. It feeds a crowd, travels well, and tastes even better the next day.
• Tested and loved for over a decade. This recipe was first shared in 2008 and is still one of the blog’s most loved and most remade dishes.

In short, this is one of those rare dishes that everyone at the table will enjoy, even the zucchini skeptics.

Ingredients: What You’ll Need

You don’t need anything fancy to make this zucchini casserole. Most of the ingredients are pantry staples, and the rest are probably sitting in your fridge. Here’s the full list with some helpful notes:

Ingredient	Amount	Why It Matters
Zucchini	4 cups (grated)	The star of the dish—grated and well-drained to avoid sogginess
Onion	1 small (chopped)	Adds sweet and savory depth of flavor
Bisquick	½ cup	Gives the casserole structure and a soft, fluffy texture
Eggs	3 whole + 2 whites	Bind everything together and create a quiche-like consistency
Parmesan Cheese	½ cup (grated)	Adds sharpness and a salty bite
Olive Oil	2 tablespoons	Keeps the casserole moist and adds a hint of richness
Fresh Herbs	2 tablespoons (chopped)	Optional but recommended—try parsley, basil, or chives
Salt	½ teaspoon	Balances out all the flavors

💡 Can’t Find Bisquick?

You can easily make your own! Here’s a quick Bisquick substitute:

• 1 cup all-purpose flour
• 1½ teaspoons baking powder
• ½ teaspoon kosher salt
• 1 tablespoon melted butter or neutral oil

Mix it all together and use just as you would regular Bisquick. Double or triple the batch to keep some on hand for future bakes!

How to Make Zucchini Casserole (Step-by-Step)

Making this zucchini casserole is as easy as mixing a bowl of pancake batter, but the results are a golden, savory, cheesy dish you’ll crave again and again.

Whether you’re a first-time cook or a seasoned kitchen pro, this recipe is foolproof and beginner-friendly.

Let’s walk through each step so you can get this dish from mixing bowl to table without a hitch.

Step 1: Preheat & Prep Your Dish

Let’s start simple. Preheat your oven to 350°F (175°C). That gives it time to heat while you prep your ingredients.

Next, grab a 9×13-inch baking dish. This size is ideal because it allows the casserole to bake evenly without being too thick or too shallow. Lightly grease the dish with olive oil or nonstick spray to prevent sticking. You want golden edges, not burnt ones!

💡 Tip: No 9×13 pan? A 9×9-inch dish works too, but expect a thicker bake. You’ll need to lower the temperature slightly and extend the baking time to ensure the center cooks through without drying out the edges.

Step 2: Grate & Drain the Zucchini

This is the most crucial step of the entire recipe and where many people go wrong.

Zucchini is made up of over 90% water. That means if you skip draining it correctly, your casserole will end up mushy and watery. And nobody wants that.

🥒 How to Grate Zucchini:

• Rinse 3–4 medium zucchinis under cold water.
• No need to peel! The skin is tender and full of nutrients.
• Use a box grater or food processor to grate the zucchini until you have approximately 4 cups.

💦 How to Drain Zucchini:

• Place the grated zucchini into a clean dish towel, cheesecloth, or nut milk bag.
• Twist and squeeze hard over the sink to remove as much water as possible.
• You should see quite a bit of liquid come out. Keep squeezing until it barely drips.
• Alternatively, let the zucchini sit between two towels on your countertop for 1 to 2 hours. This passive method helps extra moisture seep out slowly.

🧂 Pro Tip: Some people lightly salt the zucchini before squeezing to help pull out more water. Just be mindful of your total salt later in the recipe!

Step 3: Mix the Ingredients

Now for the fun part, combining everything into a big, beautiful bowl of flavor.

Grab a large mixing bowl. Add the following:

🥣 Ingredients to Mix:

• 4 cups grated and drained zucchini
• 1 small onion, finely chopped
• ½ cup Bisquick (or homemade substitute – see earlier section)
• 3 large eggs + 2 egg whites
• ½ cup grated Parmesan cheese
• 2 tablespoons olive oil
• ½ teaspoon salt (adjust to taste)
• 2 tablespoons chopped fresh herbs (like basil, parsley, or chives)

Mix everything with a large spoon or spatula until well combined. The mixture should be moist but not watery, and thick enough to spoon into your baking dish.

👩‍🍳 Kitchen Note: It’s okay if the batter looks “rustic.” The beauty of this casserole is in its homemade feel. As it bakes, the eggs and Bisquick create a structure that holds everything together beautifully.

Step 4: Pour & Bake

Time to get this baby in the oven!

• Pour your zucchini mixture into the greased 9×13 baking dish.
• Use a spatula to smooth out the top so it’s evenly distributed.
• Pop it into your preheated oven at 350°F and bake for 45 to 50 minutes.

You’ll know it’s ready when:

• The top is golden brown.
• A toothpick inserted into the center comes out clean or with a few moist crumbs.
• The edges pull away slightly from the sides of the dish.

During baking, your kitchen will start to smell like melted cheese and fresh herbs, and your stomach will start rumbling!

🍳 Troubleshooting Tip: If the top is browning too fast, loosely tent the dish with foil. If the middle is still soft at 45 minutes, give it 5–10 more minutes and check again.

Step 5: Cool & Serve

You made it! But don’t slice into your casserole just yet.

Let the zucchini casserole rest on the counter for 10–15 minutes after removing it from the oven. This allows it to firm up, making slicing much easier.

It’s tempting to dig in immediately, but trust us, this short wait makes all the difference. The flavors settle, the texture sets, and you won’t end up with a crumbling mess on your plate.

🥗 How to Serve:

Now for the best part, serving up a slice (or two). This zucchini casserole is delicious at almost any temperature:

• Warm: Right after baking, served with a fork and a smile.
• Room Temp: Perfect for brunch or a picnic.
• Cold: Leftovers straight from the fridge? Surprisingly good.

🧀 Want it extra cheesy? Sprinkle a little more Parmesan or shredded mozzarella on top during the last 10 minutes of baking.

Tips for Zucchini Casserole Success

Want to make sure your zucchini casserole turns out perfect every single time? These practical tips will help you avoid soggy middles, bland bites, and all the usual casserole mistakes. Whether you’re making this dish for the first time or the fiftieth, a few clever tweaks can elevate it from good to incredible.

1. Drain the Zucchini Thoroughly

We can’t say this enough: zucchini is full of water. If you don’t drain it correctly, your casserole could turn into a soggy mess.

• Use a clean dish towel or cheesecloth to wring out grated zucchini.
• Do it twice if you’re unsure; it’s better to be safe than sorry.
• You can also let the zucchini rest between two towels on the counter for an hour or more. The moisture will naturally seep out.

💡 Think of it like drying out a sponge; your zucchini needs a good squeeze to perform well in a casserole!

2. Let It Cool Before Slicing

Once it comes out of the oven, the casserole will still be soft and steaming inside. Let it cool for 10–15 minutes to allow it to firm up. That way, you get clean, sharp slices and better texture.

3. Use Fresh Herbs for Bright Flavor

While dried herbs are a suitable substitute, fresh herbs like basil, parsley, and chives elevate this dish to the next level. They add brightness and color that pair beautifully with the mild zucchini and sharp Parmesan.

4. Adjust Seasoning to Taste

Zucchini is naturally mild, so don’t be afraid to season your mixture well.

• Add a dash of garlic powder, onion powder, or even red pepper flakes.
• Taste the batter (before adding eggs) and tweak accordingly.

5. Customize It with Add-Ins

This recipe is a blank canvas. Want more flavor or texture? Try:

• Shredded mozzarella or cheddar for gooey, melty bites
• Chopped sun-dried tomatoes for a savory punch
• Crumbled bacon or cooked sausage for a protein boost
• Sautéed mushrooms or corn kernels for extra veggies

How to Serve Zucchini Casserole

One of the best things about zucchini casserole is its versatility. It works with almost any meal, at any time of day.

🥞 For Brunch

Hosting a weekend brunch? This casserole is a total winner on the table.

• Pair it with fresh fruit salad.
• Add turkey or chicken breakfast sausage.
• Serve with mimosas or iced coffee for a fresh and balanced spread.

It’s light, satisfying, and won’t overpower other brunch dishes.

🥗 As a Meatless Main

Need a quick and healthy dinner idea? This casserole is hearty enough to stand on its own.

• Serve with a big green salad.
• Add a slice of crusty sourdough or garlic toast.
• Pair with a cup of vegetable soup on a colder night.

You’ll be amazed how filling it is, thanks to the protein from the eggs and cheese.

🍗 As a Side Dish

Zucchini casserole also shines as a side. Its soft, quiche-like texture balances out meat dishes perfectly.

Try it with:

• Grilled chicken and roasted potatoes
• Baked salmon and asparagus
• Steak and Caesar salad
• BBQ ribs or pulled pork sandwiches at a summer cookout

🔥 Tip: Want it crispier as a side? Pop it under the broiler for 2–3 minutes before serving to get golden edges.

🍱 For Meal Prep & Packed Lunches

Zucchini casserole is the meal prep dream. It holds together well, travels easily, and tastes amazing reheated.

• Pack in airtight containers for work or school lunches.
• Slice and wrap for grab-and-go breakfasts
• Eat cold or microwave at lunchtime for a quick, healthy bite.

Storing & Reheating Tips

You made a big batch, now what? Good news: zucchini casserole stores beautifully and tastes just as delicious the next day (sometimes even better!).

🧊 Refrigeration

• Let the casserole cool completely.
• Store in an airtight container or wrap tightly with foil.
• Keeps well in the fridge for up to 3 days.

❄️ Freezing Instructions

• Slice into portions once cooled.
• Wrap each piece in foil or plastic wrap, then place in a freezer-safe bag.
• Label with the date and freeze for up to 1 month.

When ready to eat:

• Thaw in the fridge overnight.
• Reheat in the oven at 350°F for 15–20 minutes or until heated through.
• You can also reheat in the microwave, but the stove preserves the texture better.

🔁 How to Reheat Zucchini Casserole

You’ve got options:

• Microwave: Fast and easy cover and heat for 60–90 seconds per slice.
• Oven: Preheat to 350°F, cover with foil, and bake for 10–15 minutes.
• Air Fryer: For crispy edges, air fry slices at 350°F for 5–6 minutes.

🧀 Optional: Sprinkle extra Parmesan or cheese on top before reheating for that fresh-out-of-the-oven flavor.

Final Thoughts: A Casserole You’ll Come Back To

If you’ve been staring at a pile of zucchini wondering what on earth to do with it, this easy zucchini casserole recipe is your answer. It’s simple, nourishing, and endlessly adaptable. Whether you’re feeding a crowd or just prepping your weekly lunches, it hits the mark every single time.

From the crispy golden edges to the tender, cheesy center, every bite is a reminder of why this dish has stood the test of time. And the best part? You don’t need to be a pro chef or spend hours in the kitchen. Just grate, mix, bake, and enjoy.

So the next time zucchini season rolls around (or you spot a great farmer’s market deal), don’t overthink it. Make this casserole and watch it become a new family favorite.

Happy baking and don’t forget to save a slice for yourself!

More Zucchini Recipes to Try Next

Looking for more delicious ways to use up all that summer squash? Check out these zucchini-packed favorites that are just as easy and satisfying:

👉 Top Zucchini Brownies Recipe for Weight Watchers

A guilt-free chocolate treat that’s secretly healthy and crave-worthy. Moist, fudgy, and only a few simple ingredients needed.

👉 Easy & Healthy Zucchini Noodles Recipe

Your go-to low-carb dinner! Light, garlicky zucchini noodles tossed in olive oil—ready in under 15 minutes.

👉 Quick Grilled Zucchini Recipe in Just 20 Minutes!

Perfect for BBQ season! These grilled zucchini slices are smoky, tender, and perfectly seasoned for any summer plate.