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Culinary Arts

How to Roast Zucchini in the Oven With Thomas Keller

Written by MasterClass

Sep 21, 2018 • 1 min read

Chef Thomas Keller loves to cook with a vegetable at the height of its season and in this case, two summer vegetables—tomato and fresh zucchini—capture the summer in one dish. Talk to your local vegetable purveyors or home gardeners about the differences between zucchini varieties, like Goldbar yellow squash or summer squash. Return to them as a resource for any vegetable you are working with and for advice about seasonal substitutions appropriate for your local growing region.

In this preparation, Chef Thomas roasts zucchini with an easy recipe for a vierge sauce. This side dish will come together in about an hour—20 minutes of prep time, and approximately 30 minutes of cook time. Note that cook times can vary widely depending upon your oven, your cookware, and the thickness of your zucchini. You'll know this dish is done when the zucchini are completely soft, rather than when your oven timer goes off.

tk zucchini


Recipe: Oven Roasted Zucchini

Ingredient Checklist

  • 3 zucchini, green and/or Goldbar
  • 6–8 ounces canola oil*
  • Vierge sauce
  • Kosher salt
  • Finishing salt

*Chef Keller recommends that you use canola oil in this technique, as roasting requires high heat and canola has a high flash point and a neutral flavor.


  • Cutting board
  • Chef’s knife
  • 12-inch fry pan
  • Spatula
  • Paper towel–lined plate

Halve the zucchini lengthwise and score the flesh in a crosshatch pattern so that the salt can penetrate it. “Rain” or “snow” salt onto the scored side of the zucchini from a height that allows it to evenly distribute. Leave the zucchini for 10–15 minutes so that salt has time to draw out moisture, which will help maintain the density of the vegetable as it cooks. Pat the zucchini dry.

Preheat oven to 450°F.

Heat canola oil (use just enough to coat the bottom of the pan) in a 12-inch fry pan until it’s shimmering and just beginning to smoke. Add the zucchini flesh side down in the oil, adjust the heat to allow the zucchini to sear and caramelize without burning. Cook about 5 minutes, then add herbs or garlic and immediately place the pan in a 450°F oven to roast for 25–30 minutes or until the zucchini are completely soft. Transfer zucchini to paper towel–lined plate to blot excess oil.

Recipe: Accompany with a Vierge Sauce

Ingredient Checklist

  • 125 grams tomato concasse
  • 15 grams champagne vinegar
  • 5 grams shallots, minced
  • 35 grams extra virgin olive oil
  • Kosher salt to taste
  • Pinch of parsley, minced

While the zucchini is roasting, gently combine all the ingredients in a mixing bowl, and allow the flavors to blend together. The vierge sauce may be prepared up to a day in advance and stored in the refrigerator. If you refrigerate, allow the vierge to come to room temperature before serving so that the flavors unfold and the olive oil is not congealed.

Arrange the zucchini on a serving platter. Then spoon the vierge sauce over the top, following by a sprinkling of finishing salt.