Kohlrabi is a cruciferous vegetable, just like cabbage, broccoli and kale. This funny-looking vegetable is about the size and shape of an orange, with a bunch of leafy stems sticking out. It has a thick skin that can range from pale green to purplish, though the inside is always a very pale yellow.
The leaves are all edible (the freshest kohlrabi will still have the leaves attached, which can be eaten raw or cooked like any greens). The smaller bulbs tend to be more tender and flavorful, but the large ones are also fine for cooking and eating. In taste and texture, kohlrabi reminds me of peeled broccoli stems with a bit of peppery radish thrown in.
Trim kohlrabi and peel it very thoroughly (you may need a sharp knife for this; the skin is quite tough and indigestible). Slice, julienne or grate it into your salad or slaw for a great crunch and a fresh but slightly spicy flavor.
It also can be cooked — boiled, steamed, sauteed, roasted or fried. More often than not, however, I use it raw for its appealing mild flavor and pronounced crispness. When buying kohlrabi, choose smaller, unblemished bulbs that are heavy for their size; if the bulbs have leaves, cut them off, and store the bulbs and the leaves separately in plastic bags in the refrigerator for up to a week, or even a bit longer for the bulbs.