Method

• 1.
  For the potatoes, preheat the oven to 180°C and grease a 2 litre baking dish.
• 2.
  Heat the duck fat in a large frypan over medium-low heat. Add onion and thyme and cook, stirring, for 8 minutes or until soft. Add the white wine and simmer for 2-3 minutes until almost evaporated, then add the potato and stir to coat.
• 3.
  Layer the potato mixture in a baking dish, overlapping in a circular pattern. Pour over enough stock to submerge the potatoes. Cover surface closely with baking paper cut to fit, then cover pan with foil. Bake for 20 minutes, then remove the foil and paper and bake for a further 30 minutes or until stock is absorbed and potato is golden.
• 4.
  Meanwhile, combine olive oil, chopped thyme and garlic in a small bowl, then season. Brush steaks with the marinade and set aside while you make the sauce.
• 5.
  Place wine, bouquet garni and eschalots in a pan over medium-high heat. Bring to a simmer, then cook, stirring occasionally, for 3-4 minutes until reduced by half. Add the consommé, then cook for a further 15-20 minutes until reduced by half again. Strain through a sieve, then keep warm.
• 6.
  Meanwhile, preheat a chargrill pan or frypan over high heat.
• 7.
  In 2 batches if necessary, grill the steaks for 3 minutes each side for medium-rare or until cooked to your liking. Loosely cover the steaks with foil and rest for 3 minutes.

• 8.
  Stir the red wine vinegar into the sauce, then whisk in the butter to give it a nice glossy finish.
• 9.
  Divide steaks among serving plates, drizzle with sauce, then serve with the boulangère potatoes and salad leaves.