1 sweet potato, about 400 g (13 oz), scrubbed and cut into chips
2 tablespoons olive oil
salt and pepper
Place the sweet potato in a bowl, toss with the oil and season, then spread over a baking sheet. Bake in a preheated oven, 200°C (400°F), Gas Mark 6, for 25 minutes, turning occasionally, until tender and golden.
Meanwhile, spread the peppercorns over a plate and season with salt. Add the steaks and press the peppercorns firmly on to both sides.
Heat a frying pan or griddle pan until hot, drizzle the steaks with the oil and cook for 3 minutes on each side for medium, or longer for well-done. Remove from the pan, cover and leave to rest.
Add the garlic to the pan and cook for 1 minute, then stir in the crème fraîche. Bring to the boil, stirring, adding a little water if the sauce is too thick. Spoon over the steaks and serve with the chips and broccoli or green beans.