Mahogany Chiffon Cake
From Betty Crocker's New Picture Cookbook 1961, General Mills, Inc., McGraw-Hill Book Company ~ Directions are paraphrased a bit by me.
I find that for making stiff peaks, it's easiest to separate the eggs while they are still cold from the refridgerator, but let the whites come to room temperature before beating and they will loft up more nicely.
3/4 cup boiling water
1/2 cup cocoa
1 3/4 cups cake flour
1 3/4 cups sugar
1 1/2 teaspoons soda
1 teaspoon salt
1/2 cup vegetable oil
7 unbeaten egg yolks (medium)
2 teaspoons vanilla
1 cup egg whites (7 or 8)
1/2 teaspoon cream of tartar

The cookcook suggests a chocolate icing, but I prefer some kind of fresh fruit topping and whipped cream, or just enjoying slices plain and unadorned.