Roast sirloin of beef with mushrooms, brandy and roasted potatoes

For the sauce, heat the vegetable oil in a large saucepan over a moderate to high heat. Add the onions, pepper, mushrooms, thyme and garlic, then cook until soft and lightly browned

Add the brandy, red wine and the tied bunch of tarragon and reduce to a syrup. Add the chicken stock and simmer gently to reduce by half

Remove the thyme and tarragon, mix in the crème fraiche and the chopped tarragon leaves. Taste and adjust the seasoning if necessary

For the potatoes, preheat the oven to 220°C/Gas mark 7. Put all the ingredients, thyme, salt and paprika into a roasting tin, making sure the potatoes are well coated in oil, and roast in the oven for 45 minutes or until golden

In the meantime, for the beef, heat the vegetable oil in an ovenproof frying pan big enough to fit the sirloin. Season the sirloin all over and, when the oil is very hot, gently brown all over

Add the butter, garlic and herbs and allow the butter to foam. Spoon it over the meat to baste, turning often, for 5 minutes. Put the entire frying pan into the oven and turn the sirloin over every 5 minutes, basting with the butter

Remove after 15 minutes for rare, 22 minutes for medium and 30 minutes for well done. These timings are a guideline, always check the internal temperature of your meat with a probe to make sure it's done the way you want it. Allow to rest for 10-15 minutes before carving

Carve the meat and place on individual serving plates. Drizzle generously with the sauce, and place a few potatoes on the plate