Summer Squash & Zucchini Gratin Casserole Recipe: Time to Pick That Zucchini From the Garden by Melissa Vickers

Summer Squash & Zucchini Gratin Casserole Recipe: Time to Pick That Zucchini From the Garden

It’s coming up on that time of year when summer gardens are flourishing, and squash and zucchini are coming in faster than we know what to do about it. Try this creamy, cheesy squash and zucchini gratin casserole recipe that starts out on the stovetop and ends up in the oven. It tastes amazing and is really easy to prep and cook.

For this cheesy zucchini gratin recipe you'll need butter, zucchini, yellow squash, shallots, fresh garlic, heavy whipping cream, panko breadcrumbs and freshly grated Parmesan cheese. That's it!

Not only is this vegetable side dish delicious, there are so many health benefits of zucchini, too. Zucchini squash is loaded with vitamins, minerals and antioxidants, and is high in fiber and low in calories. Serve this vegetable dish with your favorite protein for dinner any day of the week.

Note: 30Seconds is a participant in the Amazon affiliate advertising program and this post contains affiliate links, which means we may earn a commission or fees if you make a purchase via those links.

Cuisine: American
Prep Time: 10 minutes
Cook Time: 15 minutes
Total Time: 25 minutes

Servings: 4


  • 2 tablespoons butter
  • 2 medium zucchini, cut into 1/4-inch rounds
  • 2 medium yellow squash, cut into 1/4-inch rounds
  • 2 shallots, minced, or 1 medium onion, thinly sliced
  • 1/2 teaspoon salt
  • 1/4 teaspoon black pepper
  • 4 garlic cloves, minced
  • 1/2 cup heavy whipping cream
  • 1 cup panko breadcrumbs (I used Italian-seasoned dry breadcrumbs), divided
  • 1/2 cup grated Parmesan cheese (divided)

Helpful Products

Recipe Notes

  • Because we try to limit salt where we can, I opted to leave out the added salt and pepper and used Italian-seasoned panko crumbs.
  • There's not need to peel zucchini or squash. The skin is loaded with nutrition! 

Here’s how to make it:

  1. In a large skillet, melt butter over medium heat. Add zucchini, squash and shallots or onions. Sprinkle with salt and pepper. Cook, stirring occasionally, until vegetables are crisp-tender, about 4 to 5 minutes. Add garlic and cook for 1 minute.
  2. Add the cream and cook until thickened, 3 to 5 minutes. Remove from heat and stir in 1/2 cup breadcrumbs and 1/4 cup cheese.
  3. Spoon mixture into greased 2-quart casserole dish. Sprinkle with remaining breadcrumbs and cheese. Bake in a preheated 450-degree F oven until golden brown about 8 to 10 minutes.

Recipe cooking times and servings are approximate. Need to convert cooking and baking measurements? Here are some kitchen conversion charts. Here's how to submit your recipes to 30Seconds.

Take 30 seconds and join the 30Seconds community, and follow us on Facebook to get recipes in your newsfeed daily.

Related Products on Amazon We Think You May Like:

30Second Mobile, Inc. is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.

Cheesy Zucchini Casserole Recipe: The Perfect Weekday Side Dish

Easy Skinny Baked Zucchini Casserole Recipe Is What's for Dinner

Chef's Easy Zucchini Fritters Recipe With Refreshing Lemon Yogurt Dipping Sauce

Love summer squash season and all the easy recipes that are so tasty.
Elisa Schmitz
Oh, how yummy, Melissa Vickers ! Our squash is growing, so hopefully I can make this recipe in the next few weeks. So fun! #yum

join discussion

Please login to comment.

recommended tips

Crispy Thai Baked Chicken Recipe: A Flavor-to-the-Bone Chicken Dinner

Brown Sugar Slow-Cooker Ham Recipe Is So Tender & Juicy (4 Ingredients)

Ham & Cheese Lover's Egg Scramble Recipe (6 Ingredients, 10 Minutes)

6-Ingredient Crispy Baked French Onion Chicken Recipe (30 Minutes)