Even to the most hardened brussels sprouts dodgers, sprout tops - the clusters of leaves that grow at the crown of the sprouts' stalk - may come as something of a revelation. These elegant, curved, purple-green leaves look beautiful - like a still life painted by a Dutch old master. In taste terms, they unite the sweet, cabbage-like freshness of young spring greens with a delicate memory of brussels sprouts, but without any of the latter's sometimes testing sulphurous undertones. They cook almost instantly to a submissive silkiness.
Although they have long been a passion shared by allotment gardeners, until quite recently, sprout tops used to lie discarded in the fields after harvest, or were fed to livestock. Happily, the word is out. Sprout tops are currently one of the hottest vegetables to have on your table, and retailers and growers are beginning to appreciate their marketpotential. So if you remain perplexed by the pre-Christmas sprout stampede, get your hands on some of this "new" (old) vegetable instead.
Why are sprout tops good for me?
Sprout tops offer all the nutritional virtues of brussels sprouts. Along with broccoli, they have the highest levels of glucosinolate compounds (which are believed to protect against cancer) of the (glucosinolate-rich) brassica family. These compounds also seem to help the body detoxify - particularly useful in the festive season. Sprout tops are vitamin-dense, and have exceptionally rich stores of two vitamins in particular: anti-inflammatory vitamin K, which like calcium, helps build bone density; and vitamin C, which helps strengthen the immune system - a winner in winter.
Where to buy and what to pay
You'll increasingly see sprout tops on growers' stalls at farmers' markets. They're creeping into supermarkets too, albeit confined to the speciality veg shelves. Guide price: £2/kg.
Joanna Blythman is the author of What To Eat (Fourth Estate, £9.99). To order a copy for £7.99 with free UK p&p, go to theguardian.com/bookshop
Sprout top, potato and chorizo soup
Based on the Portuguese caldo verde, this soup can be as hearty or as light as you wish. I have even poached a duck egg in the top as a super special treat.It can also be a really good way to use up leftover stock from cooking a ham and roast spuds and sprouts for Christmas lunch.
2 tbsp olive oil, plus extra to serve
300g cooking chorizo
2 large onions, peeled, halved, thinly sliced
4 cloves garlic, peeled and crushed
6 large potatoes, peeled and cut into small chunks
1.2 litres chicken, ham or vegetable stock
2 bay leaves
300g sprout tops, washed, dried and thick stems removed, leaves chopped
1 Heat half the oil in a large heavy-based pan over a medium heat and add the chorizo. Cook until it lets out a good amount of rich, red fat. Lift out the browned pieces of chorizo, using a slotted spoon so that the oil stays in the pan.
2 Now add the onions and the rest of the oil. Cook to soften for 7 minutes, add the garlic and cook for a couple of minutes before adding the potato. Stir the potato so that it gets a good coating of onions, garlic and chorizo oil.
3 Now return the chorizo to the pan and add the stock. Bring to the boil and simmer until the potato is just cooked. In the meantime make sure the sprout tops are dry, then whizz them in the food processor until they become little bits of green confetti.
4 Once the potato is cooked, mash some of it up to thicken the soup. Season to taste. Now add the sprout tops and simmer for about 4 minutes until all the flecks of green are well amalgamated and cooked.
5 Season to taste again and drizzle the top with olive oil to serve.
Rosie Sykes is head chef of Fitzbillies (fitzbillies.com) and co-author of The Kitchen Revolution (Ebury Press, £25). To order a copy for £19.99 with free UK p&p, go to theguardian.com/bookshop
Photo: Sprout tops - rich in vitamins C and K. Photograph: Jill Mead for the Guardian