Heat the oil in a non-stick frying pan. Reduce the heat, fry the ham and sage for approx. 10 mins. until crispy, stirring occasionally. Remove and drain on paper towels.
Cook the potatoes in boiling salted water for approx. 15 mins. until just soft, drain the potatoes, keep warm.
Place the cheese in the raclette pans and melt under a raclette grill for approx. 8 mins. Add the topping, serve with the potatoes.