Romanesco broccoli looks as if it should be in a museum rather than on a dinner plate. What is it? As its name suggests, it's related to broccoli, belonging to the same family of vegetables that also includes cauliflower, cabbage and kale. The beautiful Romanesco, with its spiral segments, is sometimes called fractal broccoli because of the resemblence of a small segment, when examined close up, to a larger piece viewed from farther away. When is it in season? Like many cruciferous vegetables, it's considered best in winter. How to choose: as you would broccoli and cauliflower. Look for heavy, tightly closed, firm heads with no bruises or soft spots. What else? It's believed by some that Romanesco broccoli is a cross between broccoli and cauliflower, but it's almost certainly a unique vegetable. How to use: you can cook Romanesco broccoli as you would cauliflower and broccoli. For a dramatic presentation, steam or boil the vegetable whole until barely tender, drain it well then cut it apart at the table and serve with cheese sauce. The best way to retain the unique shapes when cutting the raw vegetable is to put it stem-side up on the cutting board. Use a sharp knife to cut through the stem but not through the florets, then pull it apart with your hands: the vegetable will break along its natural seam. Continue to cut it in this way until the florets are the size desired (this is also the best way to cut cauliflower and broccoli). The vegetable can be blanched, tossed with olive oil, sliced garlic and chillies, then roasted. For a simple salad, blanch pieces of Romanesco until crisp-tender then toss with thinly sliced red peppers, toasted pine nuts and mustard-lemon vinaigrette. If you want a more substantial preparation, briefly blanch pieces of the Romanesco then drain and pat dry. Put the segments upright in a baking dish (you might need to trim the bottoms so they will stand). Simmer some cream with salt, black pepper, grated nutmeg and sliced garlic then pour this over the Romanesco. Sprinkle with grated gruyere and parmesan mixed with panko breadcrumbs, dot with a few pats of butter, then bake until the vegetable is tender, the cream is reduced and the top is brown and bubbling.