Potatoes en papillote

I fell in love with the papillote (paper) method around 12 years ago, making almost every fish like that, as this is how it keeps its moistness and juiciness and those lovely aromas that escape the moment you cut open the paper. But, before making this recipe, inspired by Elizabeth David, I never had an idea to make potatoes like this, yet what a fool I have been for living without a recipe so simple and divine.