In the bowl of a stand mixer, beat the egg whites, cream of tartar, vanilla and salt until stiff peaks form.
Sift 1 cup of the sugar over the beaten egg whites and beat them again.
Sift the remaining brown sugar with the flour and fold it gently into the egg whites just until combined.
Turn the batter into an ungreased 10-inch tube cake pan.
Bake at 350 degrees for 40 minutes or until the top of the cake springs back when you touch it.
Immediately after baking, turn the pan upside down and place 3 glasses of the same height underneath the pan to hold it up. Allow the cake to cool completely upside down.
To remove the cake from the pan, run a knife around the edge of the pan and the edge of the inside tube.
Remove the cake and place on a serving pan.
Serve with whipped topping sprinkled with cinnamon, or whatever topping you'd like.
If you need a cake flour replacement, take a cup of all-purpose flour and remove two tablespoons of flour from the cup. Then, add two teaspoons of cornstarch to the cup of flour. Cornstarch is a tenderizing agent, so by reducing the flour and using this, it will limit the amount of gluten that can form.