Pre-heat the oven to 200C degrees/400 degrees F/ Gas Mark 6.
Remove some of the rosemary leaves from the stalks by running your thumb and forefinger down the length of the stalk. Sharpen the ends of the rosemary skewer to make them into little arrows, then pierce them through the beef to flavor it. Chop up the rosemary leaves and press onto the beef on both sides. Cover and allow to stand for 1/2 hour until room temperature. (Beef tastes better if cooked at room temperature.)
Make the butter by bashing the garlic, summer savory and a pinch of salt in a pestle and mortar, then combine with the softened butter, mixing to flavor all of it. Put into buttered paper, roll into a sausage shape, and chill.
Cook the potatoes in boiling, salted water for about 10 to 15 minutes. Drain, then toss in the colander to chuff up.
Drizzle some oil over the beef and pat onto both sides. Heat a frying pan suitable for the oven, and cook the beef for 1 minute on each side. Remove from the pan, add the potatoes with some rosemary and bashed garlic, salt and pepper, then put the beef back into the pan. Put the pan into the oven and roast the beef and potatoes for about 30 minutes.
To serve, slice the meat and place 2 slices of the butter on top. (Freeze the remaining butter.)
(c) Jamie Oliver 2003