Green zucchini is the most common summer squash, but there are many other delightful varieties to try. Yellow and light green pattypan squash look like scalloped-edged spinning tops. Crookneck squashes have elongated goosenecks. Another variety, the Costata Romanesco squash, is rare but renowned for exceptionally sweet flavor and firm texture.
All summer squashes are harvested while immature, when their skins are tender and their flesh is moist. They can be eaten raw, which seems surprising at first but is actually a wonderful way to enjoy just-picked squash. In fact, the word "squash" comes from a Narragansett Indian word meaning "a green thing eaten raw." Summer squash can also be cooked. The vegetable's mild and adaptable flavor combines well with a wide range of ingredients, from herbaceous fresh marjoram to pungent, briny capers to mellow white cheeses.
The Native Americans were the first to cultivate summer squashes. The Cucurbita pepo plant and other members of the genus may have been grown primarily for their seeds, which were used as currency throughout the Americas. Conquistadores brought summer squash to Europe, then on to Angola and Mozambique. From there, squash traveled to India, Indonesia, and China, before making its way back to Europe by way of the Ottoman Empire and the Balkans. As it traveled around the world, the plant acclimated quickly to all warm climates and continues to be grown in abundance.
When selecting summer squash at the market, the most important feature to look for is size. Generally, the tiniest immature squashes can have an unripe, green, bitter flavor while the biggest ones can be bland and watery with larger seeds. Go for the small, firm squashes and try as many varieties as you can before their warm weather season comes to an end.
Summer Squash Tian
Tian is a Provencal-style casserole. The French word "tian" also describes the shallow, earthenware dish in which the casserole is baked. Traditionally, the recipe calls for layers of thinly sliced summer squash and tomatoes, but I like to add hearty sweet potatoes.
6 tablespoons extra-virgin olive oil
1 medium summer squash (16 ounces), sliced ¼-inch thick
1 sweet potato (12 ounces), sliced ¼-inch thick
1½ cups thinly sliced leeks, white and light green parts only, rinsed well
2 cloves garlic, minced
1 tablespoon fresh thyme leaves
1 large tomato (16 ounces), sliced ¼-inch thick
3 1/2-inch thick slices of bread
2 tablespoons grated Parmigiano
Kosher salt and freshly ground black pepper
Preheat the oven to 425ºF.
Brush the inside surfaces of a shallow 2-quart baking dish with 1 tablespoon olive oil.
In a large bowl, toss together sliced summer squash, sweet potato, leeks, garlic, thyme, 4 tablespoons olive oil, 1 teaspoon salt, and several grinds of black pepper. Arrange half the sweet potato slices in the baking dish. Top with half the squash slices, then a layer of half the tomato slices. Layer the remaining sweet potato slices, followed by the remaining squash slices, and finally the remaining tomato slices. Season with ¼ teaspoon salt and a few grinds of pepper.
Cover the baking dish with foil, and bake for 30 minutes.
Meanwhile, pulse the bread, remaining tablespoon olive oil, and Parmigiano in a food processor fitted with a metal blade until the breadcrumbs are about the size of a pencil eraser.
Remove the baking dish from the oven, discard the foil, and scatter the seasoned breadcrumbs evenly across the top. Bake, uncovered, for another 45 - 50 minutes or until the potato is tender and breadcrumbs are crisp.