Kohlrabi.

Kohlrabi, meaning "turnip-cabbage" in German, is a member of the brassica (cabbage) family, and I'm a big fan. My favourite way to prepare a kohlrabi is to trim the leaves and steam or stir-fry them as spring greens; then take the bulk of the vegetable - the swollen stem for which it is chiefly grown, about the size of a tennis ball - and cut off the outer layers to reveal the crisp delicious centre, slice or chop and eat it raw, or cut into batons and add to a stir-fry. Delicious!

"Noriko" kohlrabi growing in the polytunnel last winter.

We grow kohl rabi in the polytunnels over winter, sowing them in September or October, from which they'll be ready in March and April. We've just harvested the last of ours, with the final few now available for sale at the farm gate, having been a staple in veg boxes over recent weeks, and appearing at Pendeen Farmer's Market and our gate stall at St. Just Primary School.

"Azur star" kohlrabi just after harvesting last month.

Here's what Yottam Ottolenghi has to say about kohlrabi (taken from his book "Plenty"):-
'People always ask me what to do with kohlrabi, an often unwanted child in the organic vegetable box. It seems too healthy, too weird, too German! In actual fact, this is a wonderful vegetable. When mixed with floury root vegetables you can use it in gratins; you can shallow-fry it in olive oil and serve with garlic and chives; and you can add it to an Oriental stir-fry.'
He use it in three recipes in the book - kohlrabi and cabbage salad, "mixed grill" with parsley oil, and mushroom lasagna. Hugh Fearnley-Whittingstall also chips in with kohlrabi carpaccio, and shaved summer veg in his book "River Cottage veg every day".
Try one - I think you'll be pleasantly surprised!