Preheat the oven to 200C/400F/Gas 6.
For the peppered steak, rub the steak with the cut side of the garlic, rub with olive oil and roll in the peppercorns to coat all over.
Heat a frying pan and fry the steak for 3-4 minutes on each side, or until cooked to your liking. Remove from the heat and leave to rest in a warm place.
For the wild mushroom sauce, heat the olive oil and butter in a pan, add the onion and sauté for 3-4 minutes.
Add the garlic and fry for one minute.
Add the mushrooms and cook for 3-4 minutes. Add the wine and simmer for 2-3 minutes, then stir in the cream and season well with salt and freshly ground black pepper.
For the chips, place the sweet potato chips onto a baking sheet, drizzle with oil and sprinkle with sea salt.
Transfer to the oven and bake for 15-20 minutes, or until crisp.
To serve, place the chips onto a serving plate, top with the steak and pour over the wild mushroom sauce. Garnish with parsley.