Summer's here, and like many cooks, I'll soon be faced with the "what to do with all the excess garden vegetables" challenge. I can't say that I'm crazy about zucchini bread, and I can't keep feeding the extra tomatoes to my dog (he gobbles them up like candy). Fortunately, I've found a delicious solution that uses large amounts of these vegetables: a summer vegetable gratin—layers of fresh tomatoes and other produce like eggplant, zucchini, or squash, with a bit of cheese, a generous amount of fresh herbs, a drizzle of olive oil, and a crunchy breadcrumb topping, all melted together by slow roasting.
As the gratin cooks, the vegetables shrink, releasing their moisture and concentrating their flavor. The finished dish is a hearty blend of flavors that can stand on its own as dinner with some crusty bread, or that can be the perfect side dish for grilled meats. Leftovers, serendipitously, are better than the first day's meal.
Five steps to perfect summer gratins
Vegetable gratins aren't hard to make; they just take a little prep time and a little layering handiwork to fit them in the pan. In fact, the only way you can really ruin one of these is by undercooking it. The longer the gratin is in the oven, the more its flavors develop.
First, you need the right dish. I'd like to say that this is the excuse you needed to buy a beautiful earthenware tian made in the South of France. (A tian is the French name for an ovenproof earthenware dish, used to cook all kinds of gratins.) But I won't, because these recipes will taste just as good in a 7x11-inch Pyrex dish. An oval dish looks pretty, but any heavy, shallow, 2-quart, ovenproof dish will work.
Next, choose the freshest vegetables and herbs. In summer, this shouldn't be hard, but I've found that when I make gratins with zucchinis and squash from the grocery store (cold-stored for who knows how long) and with those winter tomatoes harvested millions of miles away, even these long-cooked gratins suffer in flavor. This doesn't stop me from making them in winter, but they taste best in summer.
To take advantage of the best vegetables and herbs you can find, don't feel constrained by the ingredient lists in the recipes here. Once you've followed one or two of the recipes to learn the method, take a look at the chart "Customizing your gratin" below for inspiration to create your own gratin. This is a great way to use all those funny round and twisted squash or tiny eggplant from the farmers' market, or even freshly harvested baby potatoes. At the start of the summer, you can use the first green tomatoes. To complement your produce, make sure that your other ingredients, including the olive oil and cheese, are of the best quality. Their flavors will play a dominant role in the finished dish.