In the food processor place the herbs, olive oil and seasoning and blend well. Rub half of the mixture over the meat and leave to marinate for about an hour.
To cook the fillet, heat a heavy cast iron pan and seal the meat, then reduce the heat and cook slowly for approximately 30 minutes. Alternatively, set the oven to Gas Mark 6, 200°C (400°F) and cook for 25-30 minutes. Cook for longer if you like it well done but the fillet is best served rare.
To Serve
Slice the fillet thinly, lay the slices on the plate and drizzle the remaining oil and herb mixture over each serving.
Cook's Notes
Individual fillet steaks could also be used in this recipe. Coat the steaks with half the herb mixture and grill or barbecue. Slice each steak for serving and drizzle the remaining herb mixture over the sliced steak.