If you prefer it a little more cooked then griddle it for longer (but you won’t be serving tataki!) This is a very generous serving of beef but it’s better to cook a larger piece. Keep some if you can’t manage all of it in one sitting. If you don’t eat red meat that often it isn’t bad for you. Great protein.
Make the sauce by whisking everything together using a fork.
Brush the beef with the oil and season, being very generous with the pepper. Heat a griddle or a frying pan over a high heat. Sear the beef on one side for 1 1/2 minutes, or until it is a really good colour, then turn over and do the other side. This is supposed to be a kind of seared carpaccio, so raw on the inside and brown all round the outside.
Transfer to a dish and pour the wine vinegar over – this just helps to tenderize the meat. Leave to cool. Slice the beef thinly then give the slices a slap with the palm of your hand – this makes it even thinner.
Wrap each slice around some sticks of cucumber. Serve these with the leaves, radishes and onions arranged alongside. Spoon the sauce over everything and put slices of pickled ginger on top of each roll of beef. Sprinkle with sesame seeds (black ones look lovely if you can get them) and serve.