Preheat the oven to 180C/350F/Gas 4.
For the steak, rub the olive oil into the meat and season well with salt and freshly ground black pepper. Heat a chargrill pan until smoking and fry the steak for 2-4 minutes on each side (for medium rare), or until cooked to your liking. Remove from the pan and place onto a warm plate to rest.
For the potatoes, heat the olive oil in an ovenproof pan and fry the potatoes for 3-4 minutes, or until lightly golden. Transfer to the oven to roast for 10-12 minutes, or until golden-brown and tender, then stir in the lemon juice and coriander.
For the carrot and coriander purée, boil the carrots with the coriander seeds in a pan until tender, then drain and pulse in a food processor along with the remaining purée ingredients until smooth.
To serve, spoon the purée onto a plate and top with the roasted potato. Thickly slice the steak and arrange on top.