3 Grill the steak for 4 minutes, turn and repeat. Transfer to a plate, cover with foil and let rest for 4 minutes. Grill the vegetables in the pan until golden and tender.
4 To make the butter, melt the butter gently with the anchovies, garlic and shallots. When the shallots are soft, add the vinegar, mustard, capers and rosemary. Stir to combine and keep warm.
5 Slice the steak against the grain and plate with the vegetables and watercress. Spoon the butter over the steak.