Preheat a chargrill and the oven to 200'c
For the sauce: Peel and finely dice the shallots and garlic. Pick the leaves from the thyme and discard the stalks.
In a sauce pan, fry the shallots in the butter until soft and caramelised. Add the garlic and thyme and cook for a further 2 minutes. Add the cognac to the pan, flambée and reduce to a syrup. Next add the chicken stock and reduce by half. Finally add the double cream and bring to the boil. Add the peppercorns and season with salt and pepper.
For the champ potatoes: Cook the potatoes in salted water until tender. Finely slice the spring onion and finely chop the parsley.
When the potatoes are cooked, crush them with a fork and mix in the spring onions, half of the parsley, seasoning and butter. Keep to one side and re-heat later.
For the mushrooms: Peel and cut the mushrooms into quarters. Peel and finely dice the garlic.
Heat a frying pan until hot. Add a splash of olive oil and then the mushrooms and allow them to colour. Season with salt and pepper and finish with the chopped garlic and the butter.
Season both sides of the steak with salt and pepper. Drizzle with a little sunflower oil. Chargrill the steak on one side and turn the steak through 90 degrees to get criss cross marks. Repeat on the other side. Once the steaks are chargrilled transfer them to a baking tray and finish cooking them in the oven to the right degree. Squeeze the steak to check how cooked it is before putting in the oven. Check the steak every 2 to 3 minutes to make sure it is not overcooked.
When you remove the steak from the oven allow it to rest for a couple of minutes. In this time re-heat the potatoes, mushrooms and sauce so as they are hot. Add the remaining parsley to the sauce just before serving.
To serve, fill a stainless steel ring with potatoes, place some mushrooms next to the potatoes, put the steak on top and finish the dish with the peppercorn sauce.
«When checking how cooked the steak is bear in mind that as it cooks the steak will get firmer. Rare steak will be very soft and well done steak will be very firm. Find somewhere in between for medium or medium rare.»