Trim the fillet of any sinew and fat and bring the beef fillet to room temperature When ready to cook sprinkle with cracked peeper and sea salt allover the fillet.
Get a heavy based skillet and get it hot drizzle a little oilve oil in and sear the beef all over until browned on all sides trying not to move it to much then place in the oven for 5 minutes.
Take out and cover with foil and let it rest.
Meanwhile cut tomatoes into wedges and slice onions thinly and toss in red wine vinegar and oilve oil season to taste.
Cut the beef fillet into thick slices and serve with tomato onion salad.