• 450 g fillet of beef (fresh not frozen)

Sauce

• 2 egg yolks, preferably free-range
• 2 tablespoons Dijon mustard
• 1 tablespoon sugar
• 2–2½ tablespoons wine vinegar
• 150 ml light olive oil or sunflower oil
• 1 tablespoon grated fresh horseradish
• 1 good teaspoon chopped parsley
• 1 good teaspoon chopped tarragon

Garnish

• 24 tiny spring onions
• watercress or flat-leaf parsley

First make the sauce. Put the egg yolks into a bowl and add the mustard, sugar and wine vinegar and mix well. Whisk in the oil gradually as though you were making mayonnaise. Finally, add the grated horseradish and chopped parsley and tarragon. Taste and season if necessary.

Chill the meat. Slice the beef fillet with a very sharp knife, as thinly as possible. Place each slice on a piece of oiled clingfilm and cover with another piece of oiled clingfilm. Roll gently with a rolling pin until almost transparent and double in size. Peel the clingfilm off the top, invert the meat on to a chilled plate, and gently peel away the other layer of film.