Raclette and Onion Salad with Pickled Walnuts

Raclette, like fondue, is trending all over again. It is a Swiss dish comprising scraped, melted cheese and not much else (though traditional accompaniments include potatoes, pickles and smoked meat). It is also the name for a type of cheese developed for the purpose. Wandering medieval cow herders reputedly used to leave their cheese by the evening fire, waiting for it to soften so they could scrape it on to their bread. Nowadays you can buy table-top electric grills and host jolly