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Mediterranean Zucchini Gratin

  • Author: Tessa
  • Total Time: 1 hour 30 mins
  • Yield: 4 entree servings 1x


A noodle-free zucchini lasagna of sorts, lightly browned zucchini slices bake between layers of parmesan, mozzarella, olives, basil, and pine nuts in this gluten-free gratin.


  • 2 T olive oil
  • 1 large red onion, peeled, halved lengthwise, then thinly sliced crosswise
  • 1/2 t dried thyme
  • Salt (sea or kosher)
  • Ground black pepper
  • 4 medium zucchini, sliced diagonally just under 1/2 inch thick
  • 18 medium to large basil leaves, sliced into thin ribbons
  • 12 to 16 pitted kalamata olives, halved lengthwise
  • 1/4 to 1/2 C finely grated parmesan
  • 4 oz. fresh mozzarella cheese, thinly sliced
  • 3 T raw pine nuts


  1. Heat 2 teaspoons oil in a wide skillet (with a lid) over medium high until hot. Add sliced onions and thyme and stir for a few minutes, until softened but not browned. Reduce heat to medium, cover, and cook until very soft and fragrant, stirring occasionally, about 10 to 12 minutes. Adjust heat as needed so the onions sizzle gently. Remove from heat, season with a sprinkle of salt and pepper (about 1/4 teaspoon each, or more to taste), and spread in the bottom of a standard sized gratin dish or pie plate.
  2. Preheat oven to 375 degrees (F). Heat another teaspoon of oil in the same skillet over medium. When hot, add half the zucchini slices in close to a single layer. Cook, stirring every couple minutes, until starting to brown, about 5 to 7 minutes. If zucchini stick to pan, turn down heat slightly. Off heat, season with salt and pepper to taste (as if you were eating them alone), then layer over the onions in the baking dish. Repeat cooking process with another teaspoon of oil and remaining zucchini, leaving the second half in the pan until needed.
  3. Over the zucchini in the baking dish, layer half the basil, half the olives, and almost half of the parmesan. Arrange mozzarella slices over the top, then repeat with another layer of zucchini, basil, olives, and parmesan, leaving a tablespoon or so of parmesan for later.
  4. Cover baking dish with foil and bake 30 minutes. Remove from oven, uncover, and carefully sprinkle with pine nuts, remaining 2 teaspoons olive oil, and remaining parmesan. Bake 10 minutes until pine nuts are lightly browned. If not browned, heat under the broiler for a couple minutes, watching almost constantly so the pine nuts don’t burn.
  5. I found it easiest to scoop, not cut, servings of this dish, being careful to keep the pine nuts on top.


The gratin is a bit watery (I prefer “juicy”)–it’s just the nature of zucchini. The liquid is actually infused with all the flavors of the gratin–thyme, onion, olives–and it wouldn’t be half bad (or bad at all) for dunking of bread. For cleaner serving, use a slotted spoon to avoid dinner plate puddles. If desired, spoon off some of the liquid before storing any leftovers.

  • Prep Time: 50 mins
  • Cook Time: 40 mins
  • Category: Gratin
  • Cuisine: Vegetarian