Preheat oven to 325 degrees. Prepare a 10" tube pan (do NOT grease). Have a bottle of wine ready (to cool the cake). Have three large bowls ready.
Bowl One: Sift flour, measure, then sift again with the baking powder, salt, and 3/4 cup sugar.
Bowl Two: egg whites
Bowl Three: Beat egg yolks, add water, and lemon juice and rind and beat at medium speed until thick and spongy (bubbly) in about 4-5 minutes. Without stopping the beaters add 3/4 of the remaining sugar gradually and vanilla and beat until the mixture is thick and spongy.
Turn mixer to the lowest speed and add the flour in four portions, scraping the sides and bottom of the bowl constantly with a rubber scraper. Beat until the batter is just smooth.
Back to Bowl Two: with an electric beater, beat the eggs until stiff enough to form shiny peaks. Then beat in the remaining 1/4 cup sugar gradually until whites form tiny peaks that curve at the tips.
Still in Bowl Two: with a rubber scraper, cut and fold the yolk/flour mixture into the whites lightly but until well mixed. Using your scraper, lightly place the batter into the tube pan.
Bake for 1 hour - until browned. When done, touch the cake and it will spring back. Remove from the oven and invert over the wine bottle and let it cool - 35-45 minutes. Remove from the pan - you will need a long knife to shave it away from the cake pan (slowly).