A 9 to 10-inch round cake pan with sides at least 3 inches high or a 10 x 4-inch tube pan (a removable bottom is helpful)
Check that one rack is in the middle of the oven and heat the oven to 325 degrees. If the pan has a removable bottom, do nothing to it. If it does not, lightly butter the bottom. Line the bottom with waxed paper or parchment paper cut to fit, and lightly butter the paper.
Thoroughly mix 1/4 cup of the sugar and the flour in a small bowl. Mix the 2 tablespoons sugar and the cinnamon in a small dish. Have all ingredients and tools at hand.
Pour the egg whites into the bowl in which you will be making the batter. Beat the egg whites with an electric mixer on medium speed for about 2 minutes, until frothy and well broken up. Add the cream of tartar and increase speed to medium-high. Beat until the whites lose their yellow cast, greatly increase in volume, and start to turn white. With the mixer running, slowly sprinkle the remaining 1 cup sugar over the whites. After 3 or 4 tablespoons, add the coffee powder. Beat until the whites become very thick, very glossy, and pale beige, and the beaters leave a deep trail. Depending on the mixer, this need only take about 3 minutes total. Reduce the speed to the lowest possible. Quickly sprinkle the flour-sugar mixture over the whites. As soon as it is all added but not completely mixed in, stop the machine and remove the bowl. With a rubber spatula or a large metal spoon, complete mixing in the flour by folding or gently stirring. Stop just as soon as the flour seems blended in. With a rubber spatula, scrape about half the 8 to 9 cups batter in the pan and spread evenly. Sprinkle the cinnamon sugar evenly over the surface. Drop spoonfuls of the remaining batter over the cinnamon sugar and spread fairly evenly. Using the spatula, trace a circle deep in the batter to release any large air bubbles. Bake until no moist patches remain in the surface cracks, the cake springs back when touched, and a cake tester inserted in the center comes out clean - about 50 minutes. Turn the pan upside down on a wire rack. Let cool completely. Loosen the edges (and tube) with a knife. Turn out the cake, loosen and remove the pan bottom, or peel off the paper. Store airtight 1 day at room temperature before serving or freezing.
Recipe courtesy of Gourmet Magazine