This is a soup to fill the soul on a cold winter evening. Leek and potato soup is actually what a good French mother will make for her child when he or she has a cold. Pureeing it and serving it with a little blue cheese makes it more elegant. Stilton is an English blue cheese that is very special at this time of year.
In a deep pan cook the shallots and leeks in the butter until translucent. Add the potatoes and chicken stock. Cook briskly until reduced by half and the potatoes are cooked. Blend with an emulsion blender or pass through a food mill. Add the cream, salt and pepper and lemon juice to taste. Serve warm with crumbled Stilton cheese.