Kohlrabi (Brassica oleracea Gongylodes Group) is a low, stout cultivar of the cabbage which has been selected for its swollen, nearly spherical, Sputnik-like shape.
The taste and texture of kohlrabi is similar to a broccoli stem or cabbage heart, but milder and sweeter, with a higher ratio of flesh to skin.
The best way of all is raw – peel them and slice thinly then eat. They beat most other raw vegetables hands down.
Kohlrabi can also be steamed or boiled. Don't peel until after they are cooked. Steam or boil until bulbs are tender, peel skin, and season with butter, salt, and pepper, a cheese sauce, or just enjoy plain.
If the leaves attached to the kohlrabi bulb are fresh and green, they can be enjoyed as a cooked green. Wash the leaves and remove the ribs. Blanch in boiling water until just wilted, 3 to 5 minutes. Drain and squeeze excess water from leaves. Chop leaves, then saute in a little olive oil or butter. Season with salt and pepper. Add a splash of vinegar or squeeze of fresh lemon juice.