Melt the butter in an enameled cast-iron saucepan or a flame ware saucepan. Add the lobster meat and simmer over low heat for a few minutes, add the milk and stir most of the time until hot, add the cream and keep on stirring. When hot, simmer for a few minutes, but do not boil. Cool. Cover and refrigerate 12 to 24 hours before serving, to develop the full flavor of the lobster. Reheat, without boiling, and, just before serving, season to taste with salt and pepper.