Preheat oven to 350 F. Using a stand mixer, beat the egg whites until frothy. Add the cream of tartar. Continue beating at medium high speed until the egg whites are opaque and are forming soft peaks.
With the mixer running, gradually beat in 1/2 cup of the sugar, until the whites form stiff peaks. Set aside.
In a medium bowl, whisk together flour, baking powder and salt.
In a large mixing bowl, use a wire whisk to stir together the yolks, water, remaining sugar, lemon zest, oil and vanilla extract until pale in color and a bit frothy.
Sift the flour mixture gradually over the yolk mixture, beating the flour well after each addition. keep beating until the batter is smooth and no lumps of flour remain.
Using a rubber spatula, gently fold the egg whites into the yolk batter in three additions. Make sure the color is uniform and no streaks off egg whites remain.
Pour the batter into a 10 inch tube pan. Run a knife across the batter to remove any air pockets. Also, tap it lightly against the counter once or twice. Bake the pineapple cake at 350 F for 55-65 minutes, or until the cake is nicely golden and springs back to the touch.
To cool the cake, let it rest on an overturned mug ( see post picture).