By Jeanne Strang
This is made with Bayonne ham, hence its name, but any jambon de campagne can equally well be used. Since they are each highly salted, no further salt is used in the recipe.
Coat a large gratin dish with butter.
Peel the potatoes and slice them into thin rounds. Remove the rind from the ham and cut it into pieces which will make whole layers in the dish. Grate the cheese. Beat the egg into the milk in a bowl.
Preheat your oven to 180°C, 350°F, Gas Mark 4