Preheat the oven to 220C/425F/Gas 7. Strip the leaves from the chard, wash and set to one side. Trim the stalks of any blemishes and cut into sticks about 5cm/2in long and 2cm/¾in wide. Bring a pan of salted water to the boil, throw in the chard stalks and return to the boil. Drain, plunge the stalks into iced water then drain again and set aside.
Heat the oil in a frying pan, add the shallots and colour them over a high heat. When they are coloured, drain off and discard the oil. Add 50g/1¾oz of the butter, the bay leaves, thyme and salt to the pan and cook for five minutes, shaking the pan from time to time, taking care not to burn the butter.
Add enough stock to just cover the bottom of the pan and allow the liquid to reduce before adding more stock to the pan. Continue with the remaining stock until the shallots are very soft and have a thick buttery and beefy glaze.
Meanwhile, heat a griddle plate or ovenproof griddle pan and season the beef well. Score the fat a little and place the steaks fat side down on the griddle. The fat will start to melt and flavour the outside of the meat.
Once the fat is melting and starting to char, leave the meat to cook for four minutes. Turn over and cook for another four minutes. Turn again to cook on its narrower side for two minutes, holding in place with tongs, turn once more to cook the other narrower side for two minutes then take it off the heat and transfer it to the oven for about six minutes for a medium steak. Let it rest for five minutes before serving.
While the steak is in the oven, heat a frying pan over a high heat and melt the remaining butter. Add the blanched chard stalks, cook for three minutes then add the chard leaves, stirring until they wilt. Season with sea salt and freshly ground black pepper, add the anchovies, capers and lemon juice and cook for two more minutes.
Using a slotted spoon, drain the chard and place on large warmed plates, reserving the sauce. Place the steaks on top of the chard, pour over the sauce and serve with the caramelised shallots.