Zucchini Casserole with Sour Cream
Zucchini is an amazing and versatile vegetable, and this humble veggie shines in this easy Zucchini Casserole with Sour Cream. This is a super easy casserole with cheese, onions, great seasoning, and zucchini. Perfect as a side dish or entree, this quick and easy casserole is perfect for zucchini lovers!
This Zucchini Casserole with Sour Cream is one of my favorites! It features sweet, tender-crisp zucchini, sweet onions, and a garlicky-cheesy-sour cream sauce with just the right amount of tang and flavor.
It’s also a great recipe to use zucchini from the garden if you have a bumper crop. Zucchini is available from just about any grocery store year-round, so don’t just wait for summer to make this easy casserole recipe.
Zucchini casserole with sour cream
You make it in an 8×8-inch baking dish, so there’s plenty to share, but not so much that you’ll be eating it for days.
I also love that the flavors in this zucchini casserole recipe are subtle enough that you can pair it with so many entrees.
When you’re looking for a cheesy vegetable casserole, give this Zucchini Casserole with Sour Cream a try – I’m sure you’ll love it!
Why I love this recipe
- It’s easy to make and is loaded with tender-crisp zucchini.
- This casserole is lower in carbs and is naturally gluten-free.
- It pairs so nicely with so many dishes. See all my suggestions below!
Gather these ingredients
- Zucchini – You’ll need 4 large ones or 6 medium-sized.
- Salt and cracked black pepper
- Butter
- Sweet white onions – Use Vidalia or Spanish onions.
- Garlic – Fresh cloves.
- Heavy whipping cream
- Sour cream
- Parmesan cheese – Shredded.
- Mozzarella cheese – Shredded.
- Gruyere cheese – Shredded.
- Fresh basil – Chopped.
How to make the best Zucchini Casserole with Sour Cream
- Preheat your oven to 425-F and grease or spray an 8×8-inch baking dish with nonstick cooking spray. Set this aside.
- Slice the zucchini into ¼-inch thick slices and add them to a large bowl. Sprinkle the zucchini with 1 teaspoon of salt and toss gently. Set this aside for 20 minutes. Do not skip this step, or your casserole will be watery!
- Drain the zucchini slices by laying them on a clean kitchen towel or paper towel and pat them dry to remove the excess water. Do both sides.
- Melt 2 tablespoons of butter in a large saucepan over medium heat and saute the onions until soft.
- Stir in the garlic and cook for an additional 30 seconds.
- Add the heavy whipping cream, sour cream, and ½ teaspoon of salt. Stir until hot and bubbly.
- Combine the Parmesan, mozzarella and gruyere cheeses in a medium bowl.
- Sprinkle ⅔ of the cheese mixture into the onion sauce and stir until thick and creamy.
- Layer the dried zucchini slices in rows in the square baking dish. You can overlap the rows.
- Pour the cheese and onion sauce over the top of the zucchini and spread evenly. Top the casserole with the remaining cheese.
- Bake at 425-F for about 20 minutes or until the zucchini is tender-crisp and the sauce is bubbly.
- Remove from the oven, top with freshly cracked black pepper and chopped basil.
Tips & substitutions
- No heavy whipping cream? You can use half and half cream or extra sour cream.
- Try to cut the zucchini all the same size for even cooking.
- Insert a fork or a knife into the zucchini to test for doneness. You should feel some resistance. For best results, ensure the zucchini is tender-crisp.
- If the top of your zucchini casserole starts to get too brown in the oven, cover it loosely with a sheet of foil.
- You can use red onion or regular cooking onions, but they’ll have more bite to them than sweet onions.
How to slice zucchini
While you can certainly use a sharp knife to slice zucchini into rounds (I use my trusty Wusthof knives), if you want truly uniform slices, a mandoline is a great tool to use. I like the OXO Good Grips Large Adjustable Mandoline Slicer, because it has a nice wide surface area for slicing big veggies, and because it has a safety shuttle that protects your fingers. It also has seven different thickness levels to choose from, so it works for a wide variety of recipes, and it costs about $30.
How to slice zucchini with a knife:
- Cut off the stem and blossom ends of the zucchini.
- Place your zucchini on a cutting board.
- Using a sharp knife, slice your zucchini crosswise into rounds.
How to slice zucchini with a mandoline:
- Cut off the stem and blossom ends of the zucchini.
- Set your mandoline slicer to the desired thickness (for this recipe it’s ¼”).
- Place trimmed zucchini underneath the safety shuttle, and move back and forth across the blade until you have the desired amount of squash rounds.
Serving suggestions
This easy Zucchini Casserole with Sour Cream pairs so nicely with so many other dishes if you want to serve it as a side. I love it with summery dishes like chicken kabobs or steaks on the grill. In the cooler months, I serve it with whole roasted chicken or a veggie-forward dish like Salmon with Wilted Greens.
Storage
Store any leftovers in an airtight container in the fridge for 3-4 days. This casserole will not freeze well; it is best eaten fresh.
Check out these awesome zucchini recipes while you’re here
Get the Recipe:
Zucchini Casserole with Sour Cream
Ingredients
- 4 large zucchini, or 6 medium
- 1 teaspoon salt
- 2 Tbsp butter melted, divided
- 1 ½ cup sliced sweet white onions
- 3-4 garlic cloves, pressed
- ½ cup heavy cream
- ½ cup sour cream
- ½ cup shredded Parmesan cheese, divided
- ¾ cup Mozzarella cheese, grated & divided
- ¾ cup Gruyere cheese, grated & divided
- ½ teaspoon salt
- Fresh basil, chopped
- Fresh cracked black pepper
Equipment
- 8×8 baking dish (I use my Pyrex baking dishes all the time)
- Large saucepan (All Clad stainless steel cookware is so great)
Instructions
- Preheat oven to 425°F. Grease a square 8×8 baking dish with butter or cooking spray. Set aside.
- Slice the zucchinis into 1/4 inch thick pieces, and place in a large bowl. Sprinkle 1 teaspoon of salt over the slices and toss gently with your hands. Set aside 20 minutes.
- TIP: This step is important as it will extract the water from the zucchini to prevent a soggy, overly wet casserole. DO NOT SKIP!
- Drain the zucchini slices by laying them on a kitchen towel or paper towel, patting them to remove as much excess water as you can (on both sides).
- In a large saucepan, melt 2 Tbsp butter over medium heat and saute the onions until soft. Stir in garlic, heavy cream, sour cream, and 1/2 tsp salt and keep sauting until the mixture is hot and bubbly.
- In a medium bowl, add all of the cheeses and mix together.
- Sprinkle ⅔ of the grated cheeses into the onion mixture and stir until melted into a cheesy sauce.
- Layer the zucchini slices in rows in the square baking dish. You will have about 4-6 rows of squash (depending on the size).
- Pour the cheese and onion sauce over the top of the zucchini and spread evenly. Sprinkle the rest of the cheese over the zucchini.
- Bake for 20 minutes; the sauce will be bubbly. Don’t overbake; take a fork and make sure the zucchini is still slightly firm and remove from the oven. Sprinkle with fresh cracked black pepper and fresh chopped basil and serve!
- TIP: If you don’t have whipped cream on hand, you can use 1 cup of sour cream.
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I’m Sandy—lover of food, family, cooking, THE BIG BOARD, travel, and bringing people together. Through great recipes and connection around the table, we become better, stronger, and more courageous people. Feasting on Life is real, and every time we do it, we grow a little more. Read more...
i absolutely love these recipes..thank you so much.. always finding new ideas and so far so Great..