Bring a medium saucepan to the boil and salt the water then add the roughly chopped potatoes.
Leave to cook for 20 minutes until soft. Drain well and return to the pot. Add the milk and butter and mash the potatoes with a potato masher. Once smooth add the crushed white peas and coriander and season to taste.
Cover with a lid and keep warm to one side.
Pre heat the oven to 220’C and remove the oven tray and line with baking paper.
Take a medium frying pan and bring to a medium/ hot heat. Place the steaks on a plate and sprinkle liberally with flakey sea salt and cracked pepper. Coat the pan with oil and begin to sear the steaks. Cook for 2 minutes each side until well coloured and sealed.
Place on the oven tray and place in the hot oven for 8/10 minutes (medium rare). Once cooked remove from the oven and allow to rest for meat to relax.
Oil the steak pan and begin to sauté the button mushrooms. Once the mushrooms brown evenly, combine the miso paste to the water with the brown sugar, add to the pan and allow to reduce to form a thick dark sauce.
To serve, take a generous portion of mash and place on a plate making a shallow well in the centre. Spoon half the mushrooms onto the mash then on a clean board cut the steaks on a 45’ angle into three pieces each. Place in the centre of the mash and spoon on the remaining sauce on and around the late. Sprinkle with roughly chopped coriander, and cracked pepper and serve.