Preheat oven to 200 degrees.
Heat a large fry pan. Rub the salt, pepper and olive oil over the meat and sear on all sides in a pan till brown. Transfer to a roasting tray and roast in the oven for 30 minutes for medium ( rule of thumb, 15 minutes per 500g for medium). Allow to rest for 15minutes before cutting.
To make the salsa, place all ingredients except the olive oil in a food processor and blend together. Scrap down the sides and blend again gradually adding the olive oil.
Cut the fillet into thin pieces and serve with the salsa verde over the top.