Preheat your waffle maker.
For the mayonnaise: whisk together the egg yolk, mustard and salt. Slowly whisk in the oil, whisking all the time.
For the steak tartare: thinly slice the spring onions. Pick and finely chop the parsley. Finely dice the capers and the gherkins. Cut the fillet steak into small dice and then mix in the onion, parsley, capers and cornichons. Season the meat with Worcestershire sauce, ketchup, tobasco sauce, mayonnaise and pepper. Chill in the fridge until ready to serve.
For the potato waffles: peel and grate the potatoes. Thinly slice the spring onions. Mix the potato and the spring onion with the cream and the egg yolks. Season with salt and pepper. Whisk the eggs whites until stiff and fold them into the potato mixture.
Pour some of the mixture onto the waffle grill and leave to cook for 5 minutes. Repeat until all of the waffle mixture is cooked.
Cut the potato waffles into strips and serve alongside the steak tartare.
«Ask your butcher for the freshest fillet or rump steak when making this recipe.»