For the steak, heat a frying pan to a moderate heat. Add a swirl of oil, with a whole garlic clove and a herb sprig. Season the steaks with salt and pepper and cook for 1½-2½ mins on each side. Add a knob of butter to the pan, allow to foam a little and baste the steaks. Cook the rounded edges too, turning to seal them well. Remove steaks to a plate and allow to rest with the pan juices for at least 5 mins.
Slice the ciabatta in half. Drizzle with a little bit of olive oil and place some thyme on top. Place under a preheated grill and toast lightly. Rub a garlic clove over the toasted ciabatta.
To serve, place the steak on one half of the ciabatta. Pour any of the juices that have seeped out from the meat over the steak. Spread mayonnaise and mustard on the other half of the ciabatta and top with some watercress. Bring the sandwich together and eat immediately.
Copyright © Gordon Ramsay