Root vegetables are usually unexceptional when boiled or steamed. They're pleasant but bland, complementing your meal but not really standing out. That changes when they're roasted. In the heat of the oven, their natural sugars caramelize and create intense and distinctive flavors, making them ideal alongside savory roasts or grilled meats. Winter squashes react to roasting in exactly the same way -- but summer squashes are rather different.
Although squashes and root vegetables have many culinary similarities, they're biologically different in important ways. Root vegetables, such as carrots and rutabagas, are intended to be a plant's winter food store. In the spring, the plant regenerates itself from the root and eventually bears seeds, to make new plants. Squash are fruits that we choose to treat as vegetables. They contain a large cavity filled with seeds, and have a hard, woody skin when mature. This means preparing them for roasting can sometimes be complicated.
Winter squashes -- such as acorn and butternut -- come in a range of skin colors, from yellow and green to vivid oranges and sometimes reds or browns. They're the most like root vegetables once they're roasted. Halve them and remove the seeds, then roast them with the skin on. The skin can be stripped off, or the flesh scraped away and mashed, after cooking. If you want evenly diced cubes of roasted squash, peel them first. That's easiest if you first blanch the squash in boiling water for a few minutes. The flesh is very hard, so you'll need some arm strength and a large, sharp knife.
Green and yellow summer squashes, such as zucchini and yellow crookneck varieties, are rather different from their winter counterparts. Their flesh isn't dense like a winter squash or root vegetable, but soft, watery and bland. They don't require peeling and seeding unless they're very large, but instead are usually just sliced or diced for roasting. Their unusually high water content means that summer squash don't roast as other vegetables do. At first they'll release a great deal of moisture as steam, which provides evaporative cooling. They'll cook and soften, but won't brown and caramelize.
For a soft and moist end result, quick roasting summer squash that has been diced, halved or sliced. Or stuff halved squash with a meat or grain filling, roast and serve with a sauce. For a more traditional roasted vegetable, slow roast summer squash for an extended period. After the bulk of its moisture evaporates, the squash -- much reduced in size -- will slowly caramelize, like a root vegetable. With the excess water gone, its flavor is also concentrated and surprisingly rich, especially when complemented by caramelized onions or fresh herbs.
- Professional Cooking; Wayne Gisslen
- On Cooking: A Textbook of Culinary Fundamentals; Sarah Labensky, et al.
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