Zucchini and Leek Gratin

Last Updated on July 7, 2021

This creamy zucchini gratin brings the comfort of your favorite casserole with the sophistication of your favorite restaurant side dish. These layers of thinly sliced zucchini and leeks are topped with crunchy parmesan breadcrumbs will have you returning for seconds or even thirds.

Zucchini and Leek Gratin

4.20 from 5 votes
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Diet: Gluten Free
Course: Side Dish
Prep Time: 55 minutes
Cook Time: 45 minutes
Total Time: 1 hour 40 minutes
Servings: 8


  • 6 medium zucchini cut into ¼" thick slices
  • 2 Tbsp kosher salt
  • 3 ea leek medium dice
  • 3 Tbsp butter
  • 2 Tbsp buckwheat flour any flour can be used
  • ½ tsp kosher salt
  • ½ tsp black pepper
  • 1 c milk
  • ½ c parmesan cheese grated

Breadcrumb Topping

  • 2 Tbsp butter melted
  • 1 c parmesan cheese grated
  • 1 c gluten-free panko any panko or breadcrumbs can be used


  • Preheat oven to 350°F.
  • Place sliced zucchini in a collander and sprinkle with 2 Tbsp kosher salt. Toss and set aside for 45 minutes. Place collander on a baking sheet to catch water.
  • Meanwhile, in a medium sauce pan on medium heat melt 3 Tbsp butter. Add cleaned, diced leeks to melted butter and sauté until translucent, approximately 5-7 minutes.
  • Add flour, salt and pepper to butter and leeks, making a roux.
  • Turn heat down to low. Gradually whisk milk into leek roux. This will be thick, a paste like consistancy. This is fine, the zucchini will release more water while baking and will loosen the thick cream sauce.

Assembling Gratin

  • Place 3 layers of paper towels on a work surface. Lay zucchini rounds in a single layer on paper towels. Take another 3 layers of paper towels to press on top of zucchini to get all excess. Repeat process until all zucchini rounds have been "dried".
  • Build gratin as a lasagna, layers. In a 9 x 13 casserole dish smear tablespoon full of leek mixture, next place single layer of zucchini on top, smear another couple spoonfulls of leek mixture on top of zucchini and finish with 2 tablespoons of grated parmesan cheese. Repeat layers until finished.
  • Top gratin with breadcrumb topping, spread out evenly and bake for 45 minutes.

Breadcrumb Topping

  • Combine all ingredients together.
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Emilie Abijanac is a graduate of New England Culinary Institute with over 20 years of catering experience in Boston. Emilie was the Sous Chef for East Meets West Catering and has worked with Kate’s Table and La Fête. Emilie was also the culinary director of ButcherBox.