Peel and skin the potatoes, then boil until soft. Mash the potatoes and set aside to cool. Slice the cheese into small cubes, about 1/4 inch in size. Thoroughly mix with the mashed potatoes whilst still hot.

To render chicken is that for cooking, cut the fat from a chicken or chicken parts and also the skin and cook over a moderate heat until as much of the fat has dissolved from the skin and the fat you cut off has melted. Add the finely chopped onion and cook until quite dark brown - you can use this rendered fat in many other dishes so make plenty and freeze.