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Zucchini, Tomato, and Potato Tian with Caramelized Onions

By America's Test Kitchen

Published on November 30, 2007

Yield

Serves 6

Zucchini, Tomato, and Potato Tian with Caramelized Onions

Ingredients

2 tablespoons extra virgin olive oil 3 slices thick-cut bacon, sliced into thin strips3 medium yellow onions, halved and sliced ¼ inch thick (about 3 cups)Salt 2 medium garlic cloves, minced or pressed through a garlic press (about 2 teaspoons)1 pound zucchini, trimmed and sliced ¼ inch thick1 pound russet potatoes, peeled and sliced ¼ inch thick1 pound plum tomatoes, cored and sliced ¼ inch thick1 teaspoon minced fresh thyme leaves Ground black pepper 2 ounces shredded Gruyère cheese (about ½ cup)

Before You Begin

Try to buy squash and tomatoes that have roughly the same diameter. Slicing the vegetables 1/4 inch thick is crucial for the success of this dish; use a mandoline or a food processor fitted with a 1/8-inch-thick slicing blade. You can also slice them carefully by hand using a very sharp knife. An ovensafe Provençal-style gratin dish can be substituted for the 13 by 9-inch baking dish, as long as it’s of similar size.

Instructions

  1. Adjust an oven rack to the middle position and heat the oven to 375 degrees. Brush a 13 by 9-inch baking dish with 1 tablespoon of the oil; set aside.
  2. Cook the bacon over medium heat until the fat has rendered, about 5 minutes. Add the onions and 1/2 teaspoon salt and cook until softened and lightly browned, 12 to 15 minutes. Stir in the garlic and cook until fragrant, about 30 seconds. Spread the onion mixture onto the bottom of the prepared baking dish.
  3. Following the illustration below, alternately shingle the sliced zucchini, potatoes, and tomatoes into a single layer of 4 tightly fit rows on top of the onions. Sprinkle with the remaining 1 tablespoon oil and thyme and season with salt and pepper. Cover the dish with aluminum foil and bake until the vegetables are tender, about 30 minutes.
  4. Remove the foil, sprinkle the cheese over the top, and continue to bake until bubbling around the edge and lightly browned on top, 20 to 30 minutes. Let rest for 10 minutes before serving.
Zucchini, Tomato, and Potato Tian with Caramelized Onions

Zucchini, Tomato, and Potato Tian with Caramelized Onions

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By America's Test Kitchen
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Yield

Serves 6

Ingredients

2 tablespoons extra virgin olive oil
3 slices thick-cut bacon, sliced into thin strips
3 medium yellow onions, halved and sliced ¼ inch thick (about 3 cups)
Salt
2 medium garlic cloves, minced or pressed through a garlic press (about 2 teaspoons)
1 pound zucchini, trimmed and sliced ¼ inch thick
1 pound russet potatoes, peeled and sliced ¼ inch thick
1 pound plum tomatoes, cored and sliced ¼ inch thick
1 teaspoon minced fresh thyme leaves
Ground black pepper
2 ounces shredded Gruyère cheese (about ½ cup)

Test Kitchen Techniques

Ingredients

2 tablespoons extra virgin olive oil
3 slices thick-cut bacon, sliced into thin strips
3 medium yellow onions, halved and sliced ¼ inch thick (about 3 cups)
Salt
2 medium garlic cloves, minced or pressed through a garlic press (about 2 teaspoons)
1 pound zucchini, trimmed and sliced ¼ inch thick
1 pound russet potatoes, peeled and sliced ¼ inch thick
1 pound plum tomatoes, cored and sliced ¼ inch thick
1 teaspoon minced fresh thyme leaves
Ground black pepper
2 ounces shredded Gruyère cheese (about ½ cup)

Test Kitchen Techniques

Ingredients

2 tablespoons extra virgin olive oil
3 slices thick-cut bacon, sliced into thin strips
3 medium yellow onions, halved and sliced ¼ inch thick (about 3 cups)
Salt
2 medium garlic cloves, minced or pressed through a garlic press (about 2 teaspoons)
1 pound zucchini, trimmed and sliced ¼ inch thick
1 pound russet potatoes, peeled and sliced ¼ inch thick
1 pound plum tomatoes, cored and sliced ¼ inch thick
1 teaspoon minced fresh thyme leaves
Ground black pepper
2 ounces shredded Gruyère cheese (about ½ cup)

Test Kitchen Techniques

Before You Begin

Try to buy squash and tomatoes that have roughly the same diameter. Slicing the vegetables 1/4 inch thick is crucial for the success of this dish; use a mandoline or a food processor fitted with a 1/8-inch-thick slicing blade. You can also slice them carefully by hand using a very sharp knife. An ovensafe Provençal-style gratin dish can be substituted for the 13 by 9-inch baking dish, as long as it’s of similar size.

Instructions

  1. Adjust an oven rack to the middle position and heat the oven to 375 degrees. Brush a 13 by 9-inch baking dish with 1 tablespoon of the oil; set aside.
  2. Cook the bacon over medium heat until the fat has rendered, about 5 minutes. Add the onions and 1/2 teaspoon salt and cook until softened and lightly browned, 12 to 15 minutes. Stir in the garlic and cook until fragrant, about 30 seconds. Spread the onion mixture onto the bottom of the prepared baking dish.
  3. Following the illustration below, alternately shingle the sliced zucchini, potatoes, and tomatoes into a single layer of 4 tightly fit rows on top of the onions. Sprinkle with the remaining 1 tablespoon oil and thyme and season with salt and pepper. Cover the dish with aluminum foil and bake until the vegetables are tender, about 30 minutes.
  4. Remove the foil, sprinkle the cheese over the top, and continue to bake until bubbling around the edge and lightly browned on top, 20 to 30 minutes. Let rest for 10 minutes before serving.

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