Whisk the egg yolk with a teaspoon of mustard. Continue whisking and gently add the ground nut oil until you get a nice smooth mixture. Season with salt and a few drops of lemon juice.
Wash the potatoes and cut into quarters (there is no need to peel them). Place them in cold salted water and bring to the boil. Cook for 4-5 minutes once the water has started to boil. Remove from the heat and drain.
In a hot pan with butter, fry the part-cooked potatoes. Add a sprig of thyme, the bay leaf and the garlic in its skin.
Continue frying the potatoes until golden brown.
Remove the bay leaf, the thyme and the garlic clove.
Finely slice the spring onions.
Chop up the capers, gherkins and the parsley.
Chop the fillet steak into 0.5cm pieces.
Place the beef, capers, gherkins and spring onions in a bowl and season with salt and pepper. Add the mustard, worcester sauce, tabasco, ketchup and chopped parsley. Check the seasoning.
Use a stainless steel serving ring to plate serve the steak tartare. Arrange the potatoes around the meat and then remove the serving ring. Serve with the mayonnaise and a green salad.
«Experiment with the seasoning of this dish to find your perfect combination.»