What is treviso in a salad

A. The market gardeners of the Veneto region of Italy excel at cultivating the red leaves of the chicory family. Over the last four centuries, they have produced variations such as ruby-coloured round heads of radiccio and chicons, properly known as radicchio di Verona, and sometimes, trevisse or treviso.

Q. What does it look like

A. It's a very distintive vegetable, perfect for livening up a dull green salad. The true raddichio tardivo di Treviso has tapering roots and brilliant magenta leaves on thick white central ribs.

It's origins are unclear; some say the 19th Century Dutch gardener Francesco Van Den Borre, who applied his methods to the Witloof - white leaf - of his native Holland, first cut heads of radicchio in the Treviso Marshes as winter set in, forcing them into a renewed second growth.

It flourished in Italy as cooks found a new vegetable between Christmas and Easter, and gardeners began an intensive-growing cycle. At the first sign of the November frosts, when the leaves of the radicchio darken, growers cut the root 15cm below the earth, trim the heads and lay them loosely bundled in troughs, under cover for transfer within two weeks to vats which hold their roots under constantly flowing spring water. Within 10 days, new roots appear, the protective summer foliage is stripped away to reveal a crisp new winter heart.

Q. How should you serve it

A. Store the heads in paper bags in the salad drawer of the fridge. Peel and trim the root, wash the leaves and shake dry. In Italy, one head per person is displayed as a centre-piece with individual saucers of dressing.

Try it in a black olive dip, lemon juice and herb dip or a simple Marsala dressing, in which you beat three tbsp of olive oil with 1 tbsp Marsala and season.

Also try treviso with toasted fontina cheese and fennel seed.

Bring a large pan of water to the boil and add 2tbsp of white wine vinegar. Preheat the oven to 180c/350F/Gas 4.

Trim and quarter three large heads of treviso, blanch them for one minute, then drain well and arrange in a wide gratin dish. Sprinkle on three finely chopped garlic cloves, a pinch of coarse sea salt and 4tbsp olive oil. Cover the dish with foil and bake for 30 minutes.

Heat the grill and slice 170g fontina cheese very thinly. Spread the slices over the treviso wedges and sprinkle on 2-3 tsp of fennel seeds. Flash under the grill until the cheese is bubbling and melted, then add a grind of black pepper and serve with toasted bread.

This could serve four as a starter, or two as a light lunch. Treviso is at its best at this time of year - try Sainsbury's or Waitrose, or you local deli.

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By Katharine MacColl