Preheat the oven to 350º F. Clean the bowl and whip of an electric mixer or a large glass bowl and the beaters of a hand mixer with white vinegar and wipe dry.
Place the egg whites and water in the prepared bowl and whip on low speed until foamy, 1 to 2 minutes. In a small bowl, whisk the sugar, salt, and cream of tartar to combine.
Raise the speed to medium, and begin to add the sugar mixture gradually, whipping to medium peaks. With such a large amount of egg whites this may take longer than you think, 8 to 10 minutes. Do not over-whip -- the egg whites should look soft and smooth, not clumpy or dry.
Add the lemon zest and vanilla extract and beat just until combined.
Add about a third of the flour, and fold to combine. This fold can be slightly more vigorous, as you’re “tempering” the batter.
Add the remaining flour in 2 to 3 additions, folding very gently to incorporate. Make sure there are no “pockets” of flour.
Pour the batter into an ungreased tube pan and smooth gently with a small offset spatula (the batter will not even out on it’s own in the oven like many cake batters do).
Bake until the top is golden brown and the structure is set (it will spring back lightly when touched), 35 to 40 minutes.
Invert the cake onto a cooling rack and cool completely. When the cake has cooled, turn it back upright run a sharp knife gently around the cake to loosen it. Do the same for the tube in the center. Turn the cake over again and it should release onto the cooling rack.
I always have three kinds of hot sauce in my purse. I have a soft spot for making people their favorite dessert, especially if it's wrapped in a pastry crust. My newest cookbook, The Book on Pie, is out on November 10th, 2020.