Preheat a heavy-based fry pan, chargrill pan or barbecue on high heat. Brush steak with extra oil and season with salt. Reduce heat to medium-high,then cook steak for 15 minutes each side for a medium-rare steak.
Place thyme, rosemary, garlic and olive oil in a shallow dish with freshly ground black pepper and a couple of pinches of coarse sea salt. Place the cooked steak in the dish, cover with foil and set aside in a warm place for 15 minutes to rest, turning once. (As a rule, you should rest meat for half as long as you cooked it, so juices redistribute and meat becomes tender.)
While the meat is resting, make the salsa. Halve the eggs and scoop out the yolks (you don’t need whites for this dish). Place the yolks in a bowl and mash with a fork. Place the bread in a separate bowl with vinegar and 2 tablespoons of warm water. Mash together with a fork until the liquid has absorbed. Add the egg yolks, tarragon, anchovy, capers and oil and stir to combine. Set the salsa aside.
To serve, cut steak away from the bone on either side and then slice fillets. Spoon some of the salsa over the meat and drizzle with the steak jus.
Notes & Tips
Order porterhouse on the bone from your butcher. Tarragon leaves are from selected greengrocers.