Cook four small pastry shells in a moderately hot oven for fifteen minutes and keep warm.
Cut truffles into small thin slices, allowing one large fresh truffle per person. Heat a small amount of butter in a pan and put in the truffles with salt and pepper, cooking lightly for a few minutes. Pour in equal quantities of Graves and sherry, bring to the boil and reduce by a third. Add a couple of cups of crème fleurette to the reduced liquid and again bring the ingredients to the boil and simmer for fifteen minutes.
Thinly slice fresh foie gras.
Use a serrated knife to slice the puff pastry shells in half. Arrange the bottom halves on individual plates or on the serving dish. Cover these with a slice of foie gras, then spoon the truffles onto the liver. Add lemon juice and seasoning to the sauce and pour it over the truffles. Cap with the pastry top and serve.