Cheesy Zucchini Gratin

Name: Cheesy Zucchini Gratin
Prep time: 20 min
Cook time: 35 min
Total time: 55 min
Yield: 8
Cuisine: American
Ingredients: 3 tablespoons butter; 1 large yellow onion, sliced; 1 clove garlic, minced; 4 medium zucchini, cut into 1/4 inch thick slices; 1/4 teaspoon ground nutmeg; 1/2 teaspoon salt; 1/2 teaspoon black pepper; 2 tablespoons all purpose flour; 1/2 cup milk; 1/2 cup heavy cream; 1 teaspoon lemon zest; 1 cup Gruyere cheese, freshly grated; 1/2 cup breadcrumbs; 1 tablespoon butter, cut into small pieces for topping

This creamy, cheesy zucchini gratin is the perfect summer side dish that even picky eaters will love.

By Recipes By Nani· 🌍 American· July 20, 2026

recipesbynani.com

Prep

20 minutes

Cook

35 minutes

Total

55 minutes

Serves

Zucchini is such a wonderful part of the summer harvest, and I am always looking for new ways to use it. This gratin has become a favorite in my kitchen because it is so comforting and indulgent. The combination of tender squash, a silky cream sauce, and a crispy cheesy topping makes it feel like a real treat on the dinner table.

It is simple to put together and works beautifully alongside roast chicken or pork chops. If you find yourself with an abundance of fresh zucchini from the garden or the farmers market, this is a wonderful recipe to keep in your back pocket.

🧺 Ingredients

3 tablespoons butter
1 large yellow onion, sliced
1 clove garlic, minced
4 medium zucchini, cut into 1/4 inch thick slices
1/4 teaspoon ground nutmeg
1/2 teaspoon salt
1/2 teaspoon black pepper
2 tablespoons all purpose flour
1/2 cup milk
1/2 cup heavy cream
1 teaspoon lemon zest
1 cup Gruyere cheese, freshly grated
1/2 cup breadcrumbs
1 tablespoon butter, cut into small pieces for topping

👩‍🍳Instructions

1
Melt 3 tablespoons of butter in a large skillet over medium heat.
2
Add the sliced onion and cook for 5 to 7 minutes until softened.
3
Stir in the garlic and zucchini slices and continue to cook for another 5 minutes, stirring occasionally.
4
Season the vegetables with nutmeg, salt, and pepper.
5
Sprinkle the flour over the vegetables and stir well to ensure everything is evenly coated.
6
Pour in the milk and cream, then add the lemon zest.
7
Cook over medium low heat for 3 to 4 minutes while stirring frequently until the sauce thickens slightly.
8
Transfer the mixture into a greased casserole dish.
9
In a small bowl, combine the grated Gruyere and breadcrumbs, then sprinkle this mixture evenly over the zucchini.
10
Dot the top with the small pieces of butter.
11
Bake for 20 minutes, or until the top is golden and bubbling, then let it rest for a few minutes before serving.

💡 Tips

Slice your zucchini into rounds of similar thickness so they cook at the same rate. This dish pairs perfectly with roasted meats like chicken or ham. Be sure to let the gratin rest for a few minutes after taking it out of the oven to let the sauce set up properly.

#vegetarian #side dish #summer #comfort food

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