My Recipe Box

Red Potato & Tomato Gratin with Leeks, Gruyère & Rosemary


Serves six to eight as a side dish; four as a main dish.

Try this gratin with Yukon Gold potatoes or substitute some of the red tomatoes with yellow, orange, or even green tomatoes.

For the leeks
  • 1-1/2 Tbs. olive oil
  • 3 cups sliced leeks (about 3 large, white and pale green parts only), washed thoroughly
For the potatoes
  • 1-1/4 lb. red potatoes, unpeeled, cut into 1/4-inch slices
  • 1/2 tsp. kosher salt; more for boiling the potatoes
  • 1-1/2 Tbs. olive oil
  • 2 tsp. chopped fresh rosemary
To assemble the gratin
  • 1 tsp. chopped fresh rosemary
  • 1-1/4 lb. ripe tomatoes, cored and cut into 1/4-inch slices
  • 1-3/4 cups grated Gruyère cheese
  • 1/2 tsp. kosher salt
  • Freshly ground black pepper to taste
  • 1-1/2 Tbs. olive oil
  • 2/3 cup fresh breadcrumbs mixed with 2 tsp.olive oil

To cook the leeks: Heat the olive oil in a medium skillet (preferably nonstick) over medium heat. Add the leeks and sauté, stirring frequently, until limp and lightly browned, about 15 minutes. Spread the leeks evenly in the bottom of an oiled 2-qt. shallow gratin dish (preferably oval). Let cool.

To cook the potatoes: In a medium saucepan, cover the potato slices with well-salted water and bring to a boil. Reduce the heat to a gentle boil and cook for 5 minutes or until the potatoes are just barely tender. Drain and rinse under cold water until cool. Pat dry. Toss the potatoes with the salt, olive oil, and rosemary.

To assemble the gratin: Heat the oven to 375°F. Sprinkle 1/2 tsp. of the chopped rosemary over the leeks. Starting at one end of the baking dish, lay a row of slightly overlapping tomato slices across the width of the dish. Prop the tomatoes against the dish at a 60-degree angle. Cover the row of tomatoes with a generous sprinkling of Gruyère. Next, arrange a row of potato slices over the tomatoes. Sprinkle again with Gruyère. Repeat with alternating rows of tomatoes and potatoes, sprinkling each with cheese, until the gratin is full.

Sprinkle about 1/2 tsp. salt and the remaining 1/2 tsp. rosemary over all and season with pepper. Drizzle with the olive oil. Mix any remaining Gruyère with the breadcrumb mixture and spread this over the whole gratin. Cook until the gratin is well-browned all over and the juices have bubbled for a while and reduced considerably, 60 to 65 minutes. Let cool for at least 15 minutes before serving.

Make Ahead Tips

ou can fully cook this gratin several hours ahead, let it cool, and then reheat it again before serving.

nutrition information (per serving):
Size : based on eight servings, Calories (kcal): 280, Fat (kcal): 18, Fat Calories (g): 160, Saturated Fat (g): 6, Protein (g): 10, Monounsaturated Fat (g): 10, Carbohydrates (mg): 23, Polyunsaturated Fat (mg): 1, Sodium (g): 420, Cholesterol (g): 25, Fiber (g): 3,

Photo: Mark Ferri

A brilliant recipe. The gratin is absolutely delicious--without any cream or butter. When I first read the recipe,potatoes and tomatoes didn't seem like the best complements, but they work wonderfully together here, and rosemary is just the right herb. Highly recommended.

This is a hit everytime I make it. I've been sharing the recipe everywhere. Make sure you slice the potatoes at least a quarter inch thick (as stated)- any thinner and they won't hold up to patting dry and tossing and you'll be layering them onto the casserole in handfuls. The microwave suggestion is a great one - I'll try that next time.

This gratin is absolutely delicious -- I have made it many times and am never disappointed. It has been a hit with all our family and friends! I microwave my red potatoes instead of boiling them so the gratin will not have too much moisture.

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