This easy, cheesy baked zucchini casserole recipe is perfect for using extra summer produce! Also called zucchini gratin, this dish uses simple ingredients and only takes 10 minutes of hands-on effort. And just like yellow squash casserole, it creates tender slices in a rich, creamy sauce. As we head into August, I know I’m not the only one with more zucchini than I know what to do with. Even though I don’t have a garden, I still have a zucchini problem: I just couldn’t resist buying way too much at the farmers’ market. Well, zucchini casserole recipes are the perfect way to use up a lot of it at once! The only thing is, I struggled with the name for this dish. Cheesy zucchini gratin? Baked zucchini casserole? Healthy zucchini bake? I couldn’t decide, so I’m using the names interchangeably. If you still have leftover veggies, try more zucchini recipes next, like zucchini fries, zucchini chips, or zucchini noodle salad.
Ingredients & Substitutions
This section explains how to choose the best ingredients for zucchini squash casserole, what each one does in the recipe, and substitution options. For measurements, see the recipe card below.
Zucchini – Use 3 medium zucchini with firm flesh and no nicks. Yellow squash would work equally well if that’s what you have on hand. Either way, slice the summer squash into thin rounds.Salt & PepperSwiss Gruyere Shredded Cheese – I used a pre-mixed shredded blend, but you can also shred Swiss and Gruyere cheese separately yourself and mix them together. Alternatively, any shredded sharp cheese, such as cheddar cheese, will work as well. Harder cheeses, like parmesan cheese, might not melt as smoothly.Brie Cheese – Helps the sauce thicken and get creamy. You could also substitute cream cheese instead.Heavy Cream – Thins out the sauce, but not too much. I recommend using cream for the thickest sauce possible. Milk, half and half, almond milk, or coconut milk can work, but you’d need to use less so that the dish doesn’t get too watery.Butter – Adds richness to the sauce. I use grass-fed butter, but any unsalted variety will work.Garlic – Use minced or crushed, fresh or from a jar.Italian Seasoning – Use a store-bought mix or make homemade Italian seasoning in minutes.
How To Make Cheesy Baked Zucchini Casserole
This section shows how to make zucchini gratin, with step-by-step photos and details about the technique, to help you visualize it. For full instructions, including amounts and temperatures, see the recipe card below.
You can saute some diced onions (or shallots), and stir them into the cheese sauce mixture, or slice the onion into rings and layer them with the zucchini slices.
Storage Instructions
Cover leftovers in an airtight container and store in the refrigerator for up to 3 days. To make sure your au gratin zucchini turns out perfect, keep these tips in mind.
Don’t skip the salting and draining step. Otherwise this recipe for zucchini casserole will stay too watery, because the zucchini will release water as it cooks. Salting beforehand removes some of the water in advance. Try different cheeses (or herbs). Fresh herbs such as rosemary would also taste delicious with this baked zucchini casserole recipe. If sauce stays watery, bake longer. Cover the top of the casserole, lower the temperature to 350 degrees F, and bake for 10-20 minutes more, until the sauce thickens. Add a crunchy topping, if desired. Use panko bread crumbs if you want, or crushed pork rinds for a low carb alternative.
Can You Freeze Zucchini Casserole?
Avoid freezing this zucchini casserole recipe, as the texture will change too much after thawing.
Reheating Instructions:
Heat in a microwave or 350 degree F oven until warm.
What To Serve With Zucchini Casserole
This dish pairs well with most proteins, but especially Italian dishes! Try these mains:
More Cheesy Veggie Casserole Recipes
If you like a baked zucchini casserole recipe, you’ll enjoy these cheesy favorites too! Share your recipe picture by tagging @wholesomeyum and hashtag it #wholesomeyum on Instagram, or in our Facebook support group, too – I’d love to see it!
