Mustard leaves

Categories: Product of the week

A potted guide to the peppery members of the brassicaceae family

“We have salad leaves galore at the moment!” chimes Vikki of Chegworth Valley, happily reeling off scores of varieties that are popping up on the stall’s Kent farm. All too often, though, salad leaves are grouped together under the indeterminate guise of ‘mixed leaves’; like a terrible band name with no thought given to the individuality of its members—except, perhaps, the lead singers.

Take the mustard leaf family. While we’re familiar with spinach and rocket, the likes of red frills, green frills, giant red mustard, and wild garlic mustard, are often overlooked. “They are all members of the brassicaceae family, and all have that distinctive peppery taste,” explains Borough Market demo chef and former head chef at River Cottage Tim Maddams, “but they vary in degree of strength, depending on the variety. Otherwise, it’s just about how pretty the leaf is.”

Green and red frills are as beautiful as they sound: “Red frills are great to add a little colour to salads, with deep purply-red leaves that are similar in shape to rocket but with a serrated edge, which gives them the appearance of having ‘frills’—as do their green counterpart,” Vikki continues. “Green frills have a milder flavour, but can still be used to give an extra kick to less flavoursome salad leaves.”

Asian-style broths
As a general rule, the bigger and more mature the leaf, the hotter its flavour. “Giant red mustard or giant black mustard, as it’s sometimes called”­—another leaf arriving in abundance at Chegworth Valley—“can become incredibly strong,” says Tim. “I have some absolutely huge giant red mustard plants at the moment, that I have overwintered in the greenhouse, and at that stage I would suggest chopping it up and chucking it into Asian-style broths. When the new crops come in, they’re obviously nice for salads but also for tipping into pasta or a stir-fry, that sort of thing.”

Bought whole, you can utilise the entire plant. “Like rocket, red frills ‘bolt’ really quickly, which means they stop flowering and set seeds, so often commercial growers simply cut the leaf and ditch the plant,” Tim explains. “If it’s grown in more of a kitchen garden environment, or on a smaller scale, however, the plant can be left to grow back once the leaves have been harvested and at some point, they will flower.

“When they do, you can use the flowers and the tips in your salads. They look lovely and they have a nice flavour as well. You can save the seeds and either re-sow them for next year or, of course, mustard seeds can be used for all sorts of dishes, particularly in Asian-style cooking.”

Wild mustard—known as ‘jack-by-the-hedge’—is also in season and can be used to add garlic notes to dishes. “Notably, the root grows quite big and it is a useful ingredient on its own,” Tim continues. “Use it like you would fresh horseradish.”

If you’re stuck for where to start, treat any mustard leaf like you would spinach, raw or cooked. “One thing I would say, though, is do not cook it as long as spinach—while it’s not unpleasant necessarily, it will go a bit odd texturally,” he muses. “Otherwise, you can totally go for it.”