1 Bring a large pan of salted water to a boil and cook the whole sweet potatoes for about 30 minutes or until softened.
2 Cut the sweet potatoes in half lengthways and scoop out some of the flesh, leaving a wall about 1 cm thick. Chop the scooped out flesh.
3 Heat the oven to 200ºC (180ºC fan) 400ºF, gas 6. Heat the oil in a pan and gently cook the onion until soft but not brown. Add the garlic and bacon and cook gently for 5 minutes.
4 Stir in the chopped potato and thyme, season with salt and pepper and pile the filling into the potato skins. place in an ovenproof dish and bake for 10 minutes. Serve garnished with chopped chives.