First off, put your steaks in the freezer, this will make them easier to dice.
Finely slice the shallots and place into a small saucepan with the red wine vinegar, a pinch of salt and pepper and the caster sugar. Bring to the boil and then let simmer. Keep cooking until all of the liquid has evaporated. Take off the heat and let cool.
Take one steak out of the freezer. as thin as you can, slice the steak in to strips, discarding any fat or sinew. Slice each strip, again, as thin as you can, and then dice these strips. Repeat with the other steak.
Put the steak pieces into a bowl and add the Worcester sauce, red wine vinegar, mustard, gin, chives and a good couple of pinches of salt and pepper. Mix well. Taste a piece of steak to check the seasoning and add more salt and pepper if needed. Place into the fridge until ready to plate up - don't leave for more than 30mins.
Roughly chop the capers.
Use a chefs ring, or cookie cutter to place the steak tartare on to the plates. Don't compact the steak down. Using a teaspoon, make a small dip in the middle of the meat and carefully place in an egg yolk. Remove the ring and place the capers, onions and cornichons around the steak, along with the toast.
Serve immediately.