Ingredients

• 150g/5oz unsalted butter, chilled and diced
• 1 turkey breast, about 450g/1lb
• 3 tbsp vegetable oil
• 100g/4oz mushrooms, quartered
• 4-6 new baby potatoes, parboiled and sliced
• 100g/4oz leeks, cut into 1cm/½in thick slices
• 1 tbsp shallot, finely chopped
• 3 tbsp dry white wine
• ½ tsp fresh rosemary, chopped, plus fresh sprigs to garnish
•   seasoning

Method

1. Preheat oven to 200C/400F/Gas 6. Divide the diced butter into five tablespoon portions.
2. Trim the turkey breast and remove any excess fat; season generously. Heat an ovenproof frying pan over a moderate heat, then add one tablespoon of the oil and one tablespoon of the butter. Allow the butter to foam, then add the turkey breast, skin side down, and cook for about 2–3 minutes until the skin is nicely coloured. Turn over for 1 minute to seal the other side. Turn back onto the skin side, transfer to a roasting tin and bake for 20 minutes or until firm to the touch.
3. Meanwhile, heat one tablespoon of the butter in a pan and add the mushrooms; season, then cook over a high heat. Heat two tablespoons of the oil and one tablespoon of the butter in another pan, add the potatoes and fry until golden.
4. Place one tablespoon of butter and two tablespoons of water in a pan, add the seasoning and leeks and cook for about 3 minutes or until the water has evaporated and the leeks are tender. Keep all of the vegetables warm.
5. Remove the turkey from the oven; allow to rest for 5 minutes.
6. Make the sauce: tip any excess oil from the roasting tin into a pan. Add the shallot and cook for 2 minutes over a gentle heat. Stir in the wine, scraping the bottom of the pan to loosen the caramelised juices. Boil until almost all of the wine has evaporated, then add three tablespoons of water and boil again until reduced. Add the chopped rosemary, then whisk in the remaining butter.
7. Spoon the vegetables on to plates. Slice the turkey and arrange on top. Pour over the sauce, garnish with rosemary and serve.