Optional: Whipped cream and finely chopped glazed pecans
Place egg whites in a large bowl; let stand at room temperature 30 minutes. For sauce, in a saucepan, combine confectioners' sugar, juice and 1/4 cup cubed butter; cook and stir over medium-low heat until sugar is dissolved. Remove from heat; stir in rum. Reserve 3/4 cup for serving.
Preheat oven to 375°. Grease and flour a 10-in. tube pan. Sift flour, baking powder, cinnamon, salt and nutmeg together twice; set aside.
In a bowl, beat egg whites on medium until soft peaks form. Gradually add 1/4 cup brown sugar, 1 tablespoon at a time, beating on high after each addition until sugar is dissolved. Continue beating until stiff peaks form.
In another bowl, beat egg yolks until slightly thickened. Gradually add 1/4 cup remaining brown sugar and the vanilla, beating on high speed until thick. Fold a fourth of the egg whites into batter. Alternately fold in flour mixture and remaining whites. Fold in melted butter.
Transfer to prepared pan. Bake on lowest oven rack 25-30 minutes or until top springs back when lightly touched. Immediately poke holes in cake with a fork; slowly pour remaining sauce over cake, allowing sauce to absorb into cake. Cool completely in pan on a wire rack. Invert onto a serving plate. Serve with reserved sauce and, if desired, whipped cream and glazed pecans.
Editor’s Note: To remove cakes easily, use solid shortening to grease plain and fluted tube pans.