Chocolate Walnut Buttercream
["1/4 lb. (4 sq.) unsweetened chocolate", "2 Tbsp. very strong coffee", "4 egg yolks", "1/4 tsp. salt", "1/2 c. sugar", "1 c. butter (1/2 lb.)", "1 c. broken walnut meats"]
["Set a mixing bowl in a basin of simmering water.", "Add the chocolate and the coffee; heat, stirring often, until chocolate is blended and melted.", "Combine the yolks, salt and sugar in another bowl.", "Set the bowl in a basin of simmering water and beat the yolk mixture rapidly with a wire whisk.", "Beat until it falls in a \"ribbon\" when the whisk is lifted.", "Spoon the chocolate into the yolk mixture.", "Return the bowl to the simmering water and continue beating.", "Gradually add the butter; beat.", "Remove the bowl from the heat.", "Continue beating until the mixture thickens and becomes spreadable.", "Add walnuts.", "Cool.", "Spread over the 2 cakes. Decorate with the 12 large walnuts."]
["chocolate", "coffee", "egg yolks", "salt", "sugar", "butter", "broken walnut meats"]