Seal the beef from both sides and place on an oven tray to finish in the oven cooked to your liking. Cut the sweet potato in 1 cm cubes and sauté on very low heat until browned in butter with a little oil, well seasoned and sprinkled with thyme leaves. Dice the apple and in a bowl mix with the chopped chilli, chilli oil and lemon zest and juice, slice the oyster mushrooms and sauté on high heat well seasoned. Dry the Parma ham slices in the oven until crispy and cut into small pieces. Place the beef on the oyster mushrooms drizzled with the dressing and sprinkled with the potatoes, pistachios, parmesan and crushed Parma ham.