1. Preheat oven to 350. Separate the eggs, and put the whites in a very clean, deep, glass or stainless steel bowl. Allow the whites to warm to room temperature (after separating) for max volume. Refrigerate the yolks for later use.
2. Whip the egg whites until foamy, then add the cream of tartar and whip the mixture until stiff but not dry.
3. Fold in the lemon juice and vanilla. Mix the flout and sugars in a bowl. Sift about 1/4 cup of the dry mix\ture over the batter. Fold in gently, but quickly. Continue until all of the mixture is incorporated, mixing as little as possible.
4. Pour the batter into an ungreased tube pan. Bake for about 45 minutes, until the top is dry and the side pulls away from the pan,.
5. To cook, use an inverted funnel or a soft-drink bottle to invert the pan. Let the cake hang for about 1 1/2 hours, until it is thoroughly set. Remove the cake from the pan before storing.