Start by placing your beef on a small plate then ahead and freeze it until firmed up slightly, it should take about 20 minutes.
Next, using a sharp knife, cut the chilled beef into 1/4-inch slices, then into 1/4-inch strips, and finely chop it. Place on a plate and refrigerate while you prepare the rest.
Chop your capers, cornichons, shallots, and parsley into fine dice, then add them to a mixing bowl alongside Worcestershire sauce and mustard, toss to combine.
Now, add the steak, fold in all the ingredients, add salt to taste, and mix again. Keep the mixture chilled until ready to assemble and eat.
Using a round mold or ramekin, press the tartare into two portions. Spread each on two plates. In each portion, make a small well in the center and gently add the egg yolk.
Serve your Gordon Ramsay Steak Tartare with cornichons or pickled vegetables, thin slices of toasted baguette, and a spoonful of mustard.