Chef Masterclass: Steve Groves' veal sweetbreads and mushroom dartois

Steve Groves, who won MasterChef: The Professionals in 2009 and is now head chef at Roux at Parliament Square, is definitely at the gourmet end of the meat-in-pastry spectrum. His dartois of veal sweetbreads and mushrooms, he says, “is a tribute to Pierre Koffmann’s legendary stuffed pig’s trotter, a dish I once ate at The Berkeley with Albert Roux”.

As with Koffmann’s dish, the filling is composed of sweetbreads, mushrooms and chicken mousse, piped into a sausage shape (a ballotine, in classical French cuisine). The wrapping, however, is puff pastry, not pig skin, with the top half of the pastry cut into a lattice to give a classic dartois appearance. “It’s a Wellington, really,” says Groves – he even includes a duxelles of mushrooms – “and there are lots of possible variations. I’m using girolles at the moment, because they’re in season, but you could use morels, as in the classic Koffmann dish, or cèpes. And you don’t need to lattice the top: it works just as well with normal pastry.”

Not that Groves forgets the pig’s trotter: he uses it to make a sauce for the dartois, submerging a trotter in white chicken stock flavoured with carrot, celery, onion, bay leaf and thyme. When the trotter’s skin is soft, after a couple of hours, he removes the skin, dices it, strains and reduces the sauce, then puts the diced skin back in, sharpening the sauce with parsley, Lilliput capers and chopped pickled onion. “This will cut through all the gelatinous fat. But any full-flavoured sauce made with reduced stock and wine would be good, too.”

It is a complex dish, but none of the steps are especially difficult, particularly if you use ready-rolled puff pastry. It is not, however, a dish to be prepared in a hurry in the middle of service. “It really helps to have everything cold when you assemble the dartois,” advises Groves. “We put the ballotine in the blast chiller after each step: 10 minutes in the freezer will have the same effect. The recipe for some of the elements will make more than you need but it’s difficult to make smaller amounts and they’ll keep in the fridge for a few days.”

Groves uses thin slices of smoked pancetta to wrap the ballotine, which adds flavour “and also, because of its high fat content, it sort of crisps the pastry from the inside,” he says. “To get the pastry crisp underneath as well as on top, it’s important to use a heavy oven tray – a cast-iron skillet is even better – and make sure it’s really hot before you put the dartois on it.”

On the plate, keep it simple: it just needs a puddle of sauce and a straightforward garnish: pomme purée, perhaps, or Jersey Royals. In summer, Groves serves it with a purée of charred sweetcorn. “If you serve it as a starter, it only needs a plain salad, maybe dressed watercress,” he says. Like all classic pastry dishes, practice makes perfect. And, if the irresistible lure of meat wrapped in pastry means that dartois flies off your menu as quickly as it does in Groves’ restaurant, you will have plenty of practice.