These rare and flavourful varieties of the more common green grass can offer chefs a seasonal twist on a popular staple of the British summer menu, says chef-consultant Russell Brown
The start of the British asparagus season is always heralded with a fair amount of excitement in the catering industry. It's a real sign that spring is here and that soon the difficulty will be not what fresh seasonal produce to put on the menu, but what to leave off.
St George's Day is the traditional start of the season for green British asparagus, but we do often see some product a few weeks earlier, even if supply is a little erratic. What is perhaps not so well known or as common is UK-grown white and purple asparagus. Many chefs will be used to buying white spears imported from the continent, but a British alternative is available.
The Chinn family at Cobrey Farms in Herefordshire are renowned in the asparagus industry. At the height of the season they employ more than 1,000 people in an operation that relies on manual labour and hightech equipment. They farm 1,000 hectares and the asparagus grading machines can process a million spears a day.
Asparagus is a fairly new side to the Chinns' business. The family started the farm with a tenancy of just 125 acres in 1925 and their first crop was potatoes, moving into asparagus in 2003. About 25% of the asparagus currently produced at Cobrey Farms is sold into foodservice.
Green asparagus yields around 2.5 tonnes per hectare, but that yield is only achieved over a 60-day growing period, with each hectare yielding around 50kg of asparagus per day.
A small but growing part of the Chinns' output is white and purple asparagus. The purple product is a different variety with a particular taste and a higher sugar level, as well as lower amounts of lignin (which makes up the tough skin on the spears). It is a challenge to grow, by all accounts, but the end product is sweeter and more tender than green asparagus. For me, the flavour is more akin to fresh peas and it lends itself to being eaten raw.
White asparagus production stands at 12 hectares currently, but is the only commercial crop in the UK and interest in it has been increasing. White asparagus is the same variety as the green, but the spears are banked up with earth and covered with black polythene to stop the emerging tips turning green through photosynthesis.
White asparagus is difficult to harvest. The tips are exposed by hand and then a long-bladed cutting tool is pushed into the soil alongside the spear. White asparagus skin is fairly tough, so the spears are usually peeled right up to the tip, and they require a longer cooking time than the green variety. The flavour is distinctive and pronounced; the stems have a crunchy texture and are succulent. Germany is a big consumer of white asparagus, where the spears are served with boiled potatoes and either melted butter or hollandaise.
With three different types of asparagus and a number of sizes, the menu choices are virtually unlimited. Jumbo asparagus, one size on offer at Wye Valley Produce, are huge spears around 4cm-5cm thick that would work as single portion on a tasting menu. At Le Roi Fou in Edinburgh, chef-patron Jérôme Henry is serving white asparagus with grilled veal sweetbreads and green harissa, while in Perranporth, Cornwall, chef Steve Marsh is pairing purple asparagus with truffled brie on a pizza at Townhouse Pizza. And at Sumas in Jersey, chef Dany Lancaster is using purple asparagus with duck eggs, morels and pomelo.
Braised white asparagus with truffle butter and crispy chicken skin
For the chicken skin
Skin from one whole chicken or from four breasts
Maldon sea salt
Lay the skin on a Silpat mat, flattening it out as much as possible. Season well with sea salt and cover with silicone paper or another Silpat. Place on a tray and lay another tray on top and weigh that down with a heavy pan or similar. Roast at 170ºC for 15-20 minutes until golden and crisp. Transfer to a cooling wire and second season.
For the asparagus
500g white asparagus, trimmed and peeled
30g unsalted butter
2tsp lemon juice
Maldon sea salt
Place the asparagus in a heavy sauté pan with the butter, lemon juice and around 75ml of water and season well. Bring to the boil then reduce the heat to a gentle simmer. Cover the pan and cook, turning the spears occasionally, until the asparagus is completely tender. Cooking time will vary according to the thickness of the spears, but expect it to take about 6-8 minutes for medium. Drain and keep warm.
For the truffle butter
75ml white wine
250ml fresh vegetable stock or white chicken
60g unsalted butter, diced
Maldon sea salt and freshly ground black pepper
10g black truffle paste
In a small pan, reduce the wine to a syrup, add the stock and reduce to 60ml. Gradually whisk in the butter, season and stir in the truffle paste.
40ml reduced chicken jus
Divide the asparagus between shallow bowls or plates and spoon over the truffle butter. Top with large shards of crispy chicken skin and add a small watercress salad. Drizzle the reduced jus around the dish.
Salad of chargrilled and raw purple asparagus with goat's cheese and oregano
For the raw asparagus salad
250g purple asparagus, trimmed
and cut into ribbons with a peeler
Maldon sea salt
50g caster sugar
50ml white wine
50ml white wine vinegar
1 sprig oregano
Extra virgin olive oil
Lightly salt the asparagus ribbons and leave for 10 minutes, then rinse off and drain. In a small pan, combine the sugar, wine, vinegar, peppercorns and oregano. Bring to the boil and allow to cool. Pour the pickling liquid over the asparagus and leave for 10 minutes.
Drain and dress with a little olive oil. The pickling liquid can be reused.
For the chargrilled asparagus
400g purple asparagus, trimmed
15ml olive oil
Maldon sea salt and freshly ground
For the goat's cheese and oregano dressing
70g soft goat's cheese
1 free range egg yolk
1tsp Dijon mustard
25ml olive oil
25g full-fat natural yoghurt
Pinch of sugar
1tsp lemon juice
Maldon sea salt and freshly ground
1dsp oregano, chopped
In a small food processor, blend the goat's cheese, egg yolk and mustard. Gradually blend in the oil and yoghurt. Season to taste using the sugar, lemon juice, salt and pepper and then stir in the oregano.
4 yellow chicory leaves cut into fine strips or a handful of frisée
Lay the chargrilled asparagus in the centre of the plates. Mix the raw asparagus with the chicory or frisée and adjust the seasoning. Mound onto the asparagus spears and spoon over a generous quantity of the goat's cheese dressing.