Traditionally, a cut wheel of raclette is pushed against the coals and the melted surface is quickly scraped over the potatoes. The cheese is replaced in front of the fire until the surface bubbles and melts again and one then scrapes it off for the next person. The following tamer method works very well.
1 onion, sliced
2 tbsp extra virgin olive oil
100g waxy potatoes (small patrone or kipfler are ideal), skinned or unskinned, whichever you prefer
100g slice raclette cheese (or other robust-tasting melting cheese)
Slowly cook the sliced onions in the olive oil until they soften, then stir and increase the heat a little, stirring frequently, until the onions are a deep golden-brown.
Separately, boil the potatoes. Drain well and toss the pan over the heat for a moment to evaporate any remaining liquid. Cut into bite-sized pieces. Tip potatoes into pan with onions and push aside to remain warm.
Heat an overhead grill. Brush a piece of aluminium foil with a trace of oil. Put cheese on oiled foil and place under grill. Have warmed potatoes and onions on a hot plate ready.
As soon as the cheese has bubbled and melted - it will only take about 2 minutes - tip it over the potatoes. Drop on the cornichons and serve and eat immediately.