Edie B.'S Chocolate Mousse
["1/3 c. butter", "3/4 c. cocoa", "5 egg yolks", "3/4 c. sugar", "5 Tbsp. rum or other liquor", "1 tsp. vanilla", "4 egg whites", "1 1/2 c. whipping cream"]
["Melt butter in a small saucepan and remove from heat.", "Stir in cocoa.", "Beat egg yolks in a small mixing bowl with 1/2 cup sugar until thick and lemon colored.", "Beat in chocolate mixture, rum and vanilla."]
["butter", "cocoa", "egg yolks", "sugar", "rum", "vanilla", "egg whites", "whipping cream"]