zucchini & tomato gratin

filed under:
tomatoes onions zucchini gratin caramelized onions

Delicious recipes are included in each issue of the South Anchorage Farmers' Market Newsletter, be sure to sign up!
subscribe to newsletter via rss • subscribe to recipes via rss • subscribe to newsletter via email
download the print-friendly version of this recipe

This recipe is exactly what to do with the big, beautiful zucchinis you can find at the Farmers’ Market! This dish is just fantastic—savory from the thyme, sweet from the onions, and just delicious from the really fresh zucchinis and tomatoes. The recipe was inspired by a recent Cook’s Illustrated recipe, although simplified. It’s easier than lasagna but I think tastes just as good (maybe even better)!

The salting and draining is necessary to keep the gratin from being soupy. It really works—after you take it out of the oven and let it sit for 10 minutes, it slices nicely without making a big lake on your plate.

3 pounds zucchini, ends trimmed and sliced into ¼-inch thick rounds
sea salt or kosher salt
2-3 large ripe tomatoes, about 1 pound
olive oil
3-4 medium onions, halved lengthwise and sliced thinly, pole to pole (about 5 or 6 cups)
½ teaspoon freshly ground pepper
3 garlic cloves, minced
1 teaspoon dried thyme, or 1 tablespoon fresh thyme
2 slices hearty bread (I prefer whole wheat sourdough)
2 medium shallots, minced (or substitute minced onion)

1. Coat a 13x9-inch baking dish with olive oil; set aside.
2. Toss zucchini slices with 1 teaspoon salt in a large bowl; transfer to a colander and let sit for about 45 minutes to let plenty of liquid drain out.
3. Toss tomato slices with ½ teaspoon salt in a bowl, and let sit for 30 minutes.
4. Meanwhile, heat 1-2 tablespoons olive oil in a large skillet over medium-high heat. Add onions, ½ teaspoon salt, and cook, stirring occasionally, until the onions are softened and golden-brown, about 15 minutes. Set the onions aside.
5. Preheat the oven to 400 degrees.
6. Drain the zucchini thoroughly.
7. Combine garlic, 3 tablespoons olive oil, ½ teaspoon pepper, and thyme in a small bowl. In large bowl, toss zucchini with the garlic mixture, then arrange in overlapping rows in the baking dish. Arrange caramelized onions in an even layer over zucchini.
8. Drain the tomatoes in the colander, then arrange the slices in a single layer on top of the onions. Bake until vegetables are tender and tomatoes are starting to brown around the edges, 40 to 45 minutes.
9. Meanwhile, process bread in food processor until finely ground.  You should have about 1 ½ cups of crumbs. Combine bread crumbs, 1 tablespoon olive oil, ½ teaspoon salt, and shallots in a medium bowl. Remove baking dish from the oven and sprinkle bread crumb mixture evenly on top of tomatoes. Bake gratin until bubbling and the bread crumbs are nicely browned, 5 to 10 minutes. Remove from the oven and let sit at room temperature for 10 minutes before serving.