Whenever I make the best zucchini casserole recipe, it disappears fast! It’s rich, cheesy, and full of flavor, yet still light enough to be a low-carb option. I love serving it as a holiday side dish because it pairs so well with turkey, ham, or chicken, but honestly, it’s just as good for a cozy weeknight dinner. If you’re looking for something easy, cheesy, and a little healthier, this is the recipe you’ll want to make again and again.
INGREDIENTS YOU’LL NEED
- 3 lbs zucchini (about 5–6 medium, sliced ¼-inch thick) – I use fresh zucchini for this casserole because it bakes up tender but still holds its shape. Slicing them evenly helps everything cook perfectly.
- 1 onion (thinly sliced) – A sweet onion adds a savory base and just the right amount of flavor without overpowering the zucchini.
- 3 cloves garlic (minced) – Fresh garlic gives the casserole that warm, homemade flavor that makes it irresistible.
- 3 tbsp butter – I melt this down to start the roux—it adds richness and a buttery taste to the sauce.
- 3 tbsp all-purpose flour – This combines with the butter to make a smooth base that thickens the creamy cheese sauce.
- 1 ½ cups whole milk (warm) – I like using warm milk so it blends easily into the roux and keeps the sauce silky.
- ½ cup heavy cream – The cream makes the sauce extra rich and velvety, perfect for a cheesy casserole.
- 1 tsp Dijon mustard – Just a little Dijon gives a subtle tang that brings out the flavor of the cheese.
- 1 tsp salt – This balances the flavors and makes the zucchini and cheese really pop.
- ½ tsp black pepper – I like a little peppery bite to balance out the creaminess.
- ½ tsp paprika (optional, for color) – A sprinkle of paprika adds a touch of warmth and a pretty golden color on top.
- 2 cups sharp cheddar cheese (shredded, divided) – I stir some into the sauce for creaminess and save the rest for that gooey, cheesy topping.
- ½ cup Parmesan cheese (grated) – Parmesan gives the casserole a nutty, salty kick that pairs perfectly with the zucchini.
- ¾ cup breadcrumbs (panko) – Panko makes the topping crunchy and golden brown when baked.
- 2 tbsp olive oil (for topping) – I toss the breadcrumbs in olive oil to make sure they crisp up nicely in the oven.
WHY I LOVE THIS RECIPE
- I love making this zucchini casserole for the holidays because it’s a cozy, cheesy side dish that feels special but is still super easy to put together.
- It’s low-carb, so I can enjoy a hearty, cheesy casserole without feeling weighed down by heavy starches.
- The combination of creamy cheese sauce, tender zucchini, and a crunchy topping makes this dish one of those comfort foods I could eat any night of the week.
HOW TO MAKE CHEESY ZUCCHINI CASSEROLE?
- Prep the Zucchini:
Place sliced zucchini in a colander, toss with 1 tsp salt, and let sit 20–30 minutes. Pat very dry with paper towels (or squeeze gently). This step removes excess water.
- Make the Cheese Sauce:
In a saucepan, melt butter over medium heat. Add onion and sauté 5 minutes until soft; add garlic and cook 1 minute. Stir in flour and cook 1 minute (makes a roux). - Add the Milk and Cheese:
Whisk in warm milk + cream gradually until smooth and thickened (about 5 min). Stir in Dijon, paprika, 1 ½ cups cheddar, and Parmesan. Taste and season with more salt/pepper if needed. - Assemble the Gratin:
Preheat oven to 400°F (200°C). Layer half the zucchini in a greased 9×13 baking dish. Pour over half the cheese sauce. Repeat with remaining zucchini + cheese sauce. Top with the remaining ½ cup of cheddar. - Add topping:
Mix breadcrumbs with olive oil or melted butter. Sprinkle evenly on top. If you trying to keep things really low-carb, skip this step. - Bake:
Bake uncovered 25–30 minutes until bubbly and golden. If topping browns too quickly, tent lightly with foil for the last 10 minutes. Let it rest 10 minutes before serving (this helps it set and prevents runny sauce).
FAQ – FREQUENTLY ASKED QUESTIONS
Yes! I love making this zucchini casserole a day before the holidays. I just assemble it, cover it, and refrigerate it. When I’m ready, I bake it fresh so it’s hot, cheesy, and bubbly.
The trick is to slice the zucchini evenly and let it drain a little before baking. That way, my easy zucchini casserole comes out creamy instead of soggy.
Yes! To keep it more low-carb (13 carbs per/serving), I swap the breadcrumbs for crushed pork rinds or just sprinkle extra cheese. It’s still creamy and satisfying.
Yes! That’s one of my favorite things about this recipe. Since it’s made with fresh zucchini, cheese, and cream, it makes the perfect low-carb zucchini casserole for dinner or a holiday side dish.
RECIPE SUBSTITUTIONS AND VARIATIONS
- Swap the cheese – I usually make this a cheesy zucchini casserole with sharp cheddar, but sometimes I switch it up with mozzarella, Monterey Jack, or Gruyère for a different flavor.
- Make it meatier – If I want this zucchini casserole recipe to be a full dinner, I’ll add cooked chicken, ground turkey, or even crispy bacon. It makes it hearty and filling.
- Low-carb breadcrumb topping – To keep this a true low-carb zucchini casserole, I’ll skip the panko and use crushed pork rinds or almond flour mixed with Parmesan for crunch.
- Add extra veggies – When I have extras in the fridge, I’ll mix in mushrooms, spinach, or even broccoli. It makes the easy zucchini casserole more colorful and nutrient-packed.
- Turn it into a breakfast bake – I’ve also whisked in a few eggs and baked it into a zucchini egg casserole. It’s perfect for brunch or meal prep.
TIPS FOR PREPARING PERFECT ZUCCHINI CASSEROLE
- Drain the zucchini well – I always salt my slices and let them sit for 10–15 minutes, then pat them dry. This keeps my zucchini casserole recipe from turning watery.
- Layer the cheese – Instead of adding it all at once, I like to layer the cheddar and Parmesan in between the zucchini. It makes the cheesy zucchini casserole extra gooey and flavorful.
- Bake until golden – For the best texture, I keep baking until the top is bubbly and golden brown. That’s when my easy zucchini casserole is perfectly done.
WHAT IS COMMONLY SERVED WITH CREAMY ZUCCHINI CASSEROLE?
When I make this zucchini casserole, I usually serve it with roasted chicken or baked salmon because it balances the cheesy richness. For a lighter meal, I’ll pair it with a fresh garden salad on the side. During Thanksgiving and Christmas Dinner, I love serving this easy zucchini casserole right next to turkey or ham—it fits perfectly on the table.
HOW TO STORE AND REHEAT LEFTOVER ZUCCHINI CASSEROLE BAKE?
When I have leftovers from this zucchini casserole, I store them in an airtight container in the fridge for up to 3 days. To reheat, I usually pop it in the oven at 350°F until it’s warm and bubbly again. If I’m in a rush, the microwave works too, but the oven keeps the casserole nice and crispy.
CAN BAKED CHEESY ZUCCHINI CASSEROLE BE FROZEN FOR LATER?
Yes, this zucchini casserole can be frozen, but I always let it cool completely first. I wrap it tightly or store it in a freezer-safe container and keep it frozen for up to 2 months. When I’m ready to enjoy it again, I thaw it overnight in the fridge and reheat it in the oven so it tastes fresh and cheesy.
LOOKING FOR MORE DELICIOUS ZUCCHINI RECIPES? TRY THESE!
Quick Chicken Mushroom & Zucchini Stir-Fry
Moist & Savory Feta Dill Zucchini Bread
Protein-Packed Triple Meat Zucchini Casserole
Best Garden Fresh Zucchini Soup
FINAL THOUGHTS
This zucchini casserole has quickly become one of my favorite holiday side dishes—it’s cheesy, cozy, and perfect for family gatherings. I love that it’s low-carb yet still feels rich and comforting, making it a crowd-pleaser for both weeknights and special occasions. If you give this recipe a try, leave me a comment and let me know how it turned out for you!
The Best Zucchini Casserole Recipe – Easy & Cheesy
Equipment
- Casserole Dish
Ingredients
- 3 lbs zucchini (about 5–6 medium, sliced ¼-inch thick)
- 1 onion (thinly sliced)
- 3 cloves garlic (minced)
- 3 tbsp butter
- 3 tbsp all-purpose flour
- 1 ½ cups whole milk (warm)
- ½ cup heavy cream
- 1 tsp Dijon mustard
- 1 tsp salt
- ½ tsp black pepper
- ½ tsp paprika (optional, for color)
- 2 cups sharp cheddar cheese (shredded (divided))
- ½ cup Parmesan cheese (grated)
- ¾ cup breadcrumbs (panko)
- 2 tbsp olive oil (for topping)
Instructions
- Prep the zucchini so it doesn’t get mushy: Place sliced zucchini in a colander, toss with 1 tsp salt, and let sit 20–30 minutes. Pat very dry with paper towels (or squeeze gently). This step removes excess water.
- Make the cheese sauce: In a saucepan, melt butter over medium heat. Add onion and sauté 5 minutes until soft; add garlic and cook 1 minute. Stir in flour and cook 1 minute (makes a roux). Whisk in warm milk + cream gradually until smooth and thickened (about 5 min). Stir in Dijon, paprika, 1 ½ cups cheddar, and Parmesan. Taste and season with more salt/pepper if needed.
- Assemble the gratin: Preheat oven to 400°F (200°C). Layer half the zucchini in a greased 9×13 baking dish. Pour over half the cheese sauce. Repeat with remaining zucchini + cheese sauce. Top with remaining ½ cup cheddar.
- Add topping: Mix breadcrumbs with olive oil or melted butter. Sprinkle evenly on top.
- Bake: Bake uncovered 25–30 minutes until bubbly and golden. If topping browns too quickly, tent lightly with foil for the last 10 minutes. Let rest 10 minutes before serving (this helps it set and prevents runny sauce).
