In a medium saucepan over low heat, heat lobster in the butter for 2 to 3 minutes. Add salt, cayenne pepper, and sherry. Mix beaten egg yolks with the half-and-half and add to lobster. Cook, stirring constantly, until lobster newburg is thickened and heated through, but do not bring to a boil. Serve lobster newburg over buttered toast or pastry shells. Lobster Newburg recipe serves 4.