If someone were to tell you that they were going to serve you an eggplant-tomato gratin, it is likely that you would immediately have a mental picture of something like eggplant parmesan...layers of eggplant in a rich tomato sauce. I love that type of gratin. I posted a French version last summer. But this gratin is nothing like that. It has much more in common with the Summer Squash Gratin that I posted last month—layers of vegetables with herbs, olive oil and breadcrumbs. Unlike that gratin (and the aforementioned eggplant parmesan-style of gratin), this one is relatively quick to prepare—provided you have all of the ingredients on hand. And as with many of my recipes, if you have a few herbs growing in your garden, and you shop at your farmers' market, you probably have most of these ingredients in your refrigerator (or your pantry) already.
This gratin is patterned after one I found in the cookbook Chez Panisse Vegetables. The original recipe uses sweet summer onions instead of leeks. So even if no one at your farmers' market has leeks, you can still make a similar gratin since there will certainly be several growers who will have onions. To make the gratin with onions, thinly slice or finely chop two or three onions and wilt them in the butter and olive oil instead of the leeks.
In looking back over previous posts, I'm a bit surprised to see that I have not yet written a post that included a description of how to clean a leek. Leeks grow in sandy soil and can be very gritty—they should always be carefully cleaned. There are few things more unpleasant (or irritating if you have spent a lot of time preparing a dish) than taking a bite of food and getting a mouthful of grit.
To clean a leek, first cut as directed in the recipe. Drop the cut leeks into a large bowl filled with water. Swish them around and then allow them to stand for a minute or two so that any dirt, sand or grit can settle to the bottom of the bowl. Lift the leeks out of the bowl with a large slotted spoon or a bowl sieve and transfer to another bowl or a colander. (Don't pour the contents of the bowl—leeks and water—into a colander because all of the dirt and grit will be poured back over the leeks.) Rinse the bowl and fill with water again. Add the leeks and proceed as before. Repeat the rinsing and draining process with fresh changes of water until there is no grit remaining in the bowl after the water has been poured off.
Whether you use leeks or onions, this light and flavorful gratin will make a wonderful side dish for a hot summer evening. It can of course be served piping hot, but the flavors seem more pronounced when it has been allowed to cool until it is just tepid. It is the perfect accompaniment to grilled or sautéed lamb or chicken (along with a green vegetable). Or, if you prefer a meatless meal, you could serve it with a green salad, some goat cheese and a nice loaf of crusty bread.
3 medium leeks, white and tender green only, halved lengthwise, thinly sliced and rinsed in multiple changes of water
2 cloves of garlic, minced
1 bay leaf (fresh, if you can get it)
salt & pepper
1 T. butter
2 T. extra virgin olive oil, plus more for drizzling
1 large globe eggplant (about 1 lb.)—see note below
3 tomatoes (about 1 1/2 lbs.)—see note below
2 to 3 T. chopped herbs (winter savory, thyme, marjoram and/or oregano)
1/2 c. Toasted breadcrumbs (recipe below)
In a large sauté pan set over medium heat, wilt the leeks in the butter and olive oil with the garlic and bay leaf. Season with salt and pepper. When the leeks are tender and their liquid has evaporated (after 20 to 30 minutes), spread in an even layer in the bottom of an oiled gratin or 2 1/2 quart shallow baking dish (discard the bay leaf); set aside. (Leeks may be wilted ahead. Bring to room temperature before building the gratin.)
If the peel of the eggplant seems tough, "stripe" the eggplant by peeling uniformly spaced strips of peel off in lengthwise strips. Slice the eggplant and tomatoes into ¼-inch thick rounds.
Arrange the eggplant and tomatoes on top of the leeks in overlapping rows of alternating slices of eggplant and tomato. Each slice should cover the previous slice by at least two-thirds. Season generously with salt and pepper and scatter the herbs over all. Drizzle generously with olive oil and cover with foil.
Bake in a preheated 400° oven until the eggplant is very tender—about 45 minutes.
Remove the foil and cover the gratin with the toasted breadcrumbs. Continue to bake until the juices are reduced and thickened—another 10 to 15 minutes. Remove from the oven. Let the gratin rest for at least 5 to 10 minutes before serving. Serve hot or tepid. Serves 6
Note: Try and select eggplant and tomatoes that are roughly the same circumference. In some cases this may mean using 2 or 3 Japanese eggplant instead of the globe eggplant.
Toasted Breadcrumbs: In a food processor, process sliced/torn bread (crusts removed if very hard), until bread is in uniform soft crumbs. Spread crumbs on a rimmed cookie sheet and “toast” in a 350° oven until golden brown and dry, stirring occasionally (about 10 minutes). Drizzle with some olive oil and toss to combine. Crumbs can be used immediately or cooled and stored airtight at room temperature for a week or so.