Zucchini and Tomato Tian with Caramelized Onions—Tian de Courgettes aux Tomates
Why This Recipe Works
Hailing from Provence and named for the region's popular terra-cotta dishes, tian is a combination of summer vegetables perfumed with olive oil and thyme and crusted with Gruyère cheese. The trick to a great tian is figuring out how to ensure perfectly cooked vegetables; mushy or undercooked vegetables will not do. We lined the dish with a layer of caramelized onions, to which we added some minced garlic to achieve full aromatic flavor. Similar-sized zucchini and summer squash, and plum tomatoes, which have a similar diameter to squash, made up the rest of the vegetables. Slicing them all on a mandoline gave us perfect slices in seconds. Alternating the vegetable slices and keeping them fairly tightly shingled gave us the look we wanted and kept the whole dish sliceable. As for cooking the tian, we found that covering the baking dish with foil trapped the heat and partially steamed the vegetables, allowing them to keep their moisture. After they'd steamed for 30 minutes, we sprinkled cheese over top and returned the dish to the oven for the second phase of cooking.