Method

• 1.
  Preheat oven to 180°C.
• 2.
  For the gratin, layer sweet potato, onion, garlic, thyme and rosemary in a shallow casserole or ovenproof dish, seasoning between layers.
• 3.
  Pour over the wine and cream, then cover with foil and bake for 40 minutes, or until potato is tender.
• 4.
  Remove foil, and scatter over parmesan and butter. Bake for another 30 minutes, or until golden and bubbling.

• 5.
  Meanwhile, place the onion, garlic, thyme and rosemary in a saucepan. Add stock and enough water to eventually cover the beef.
• 6.
  Bring to a simmer, then add the beef and simmer for 5 minutes. Remove from the heat and set aside for 20 minutes. Drain beef and pat dry. Brush with oil and season.
• 7.
  Heat a large frypan over high heat. Add the beef and sear for 4-5 minutes, turning until all sides are slightly charred.
• 8.
  Rest, covered in foil, for 10 minutes, then slice.
• 9.
  Serve with sweet potato gratin, mustard, green salad and any pan juices.