If you buy a good piece of beef, you need do nothing more than rub it with a little olive oil and season it generously before putting it into a very hot oven. The fat will baste the meat as it cooks, resulting in a beautifully flavorful roast. Don’t forget to leave the meat to relax for at least 15 minutes so that it has time to reabsorb its juices. If you want to have a traditional meal, serve with roasted potatoes and steamed broccoli. Alternatively, serve at room temperature with a salad
Preheat the oven to 450°F. Put the beef in a large roasting pan and drizzle with the olive oil. Sprinkle over some salt, pepper, and the chopped rosemary and rub the seasoning all over the beef. Turn the beef so that the fat is on top. Roast in the hot oven for 20 minutes, then reduce the heat to 400°F. Roast for 5–10 minutes per pound for medium-rare meat, or 10–15 minutes per pound for medium. Turn the beef halfway through cooking for an even roast.
Transfer the beef to a warm platter, cover loosely with foil, and leave to rest for 15–20 minutes. To make the gravy, pour off any excess fat from the roasting pan, leaving behind a couple of tablespoons, then place the pan over medium heat. Add the shallots, garlic, and a little salt and pepper. Cook for about 4–6 minutes, stirring frequently, until the shallots begin to soften. Add the flour and stir for a few more minutes.
Pour in the vinegar and red wine and bring to a boil. Add the stock and return to a boil for about 10 minutes until the sauce has reduced and thickened, then stir in the tarragon.
Carve the beef thinly and serve the gravy in a warm gravy boat.