Preheat the oven to 350 degrees F.
Stir the flour, baking powder, salt, and lemon zest together in a large bowl.
Make a well in the center, and add the egg yolks, water, oil, and lemon extract.
Starting in the center and working your way outwards, whisk the liquid ingredients together, gradually drawing the dry ingredients into the batter.
In a separate, very clean, grease-free bowl, whip the egg whites and lemon juice together on medium-low speed until foamy.
Add the sugar in a very slow, steady stream while continuing to whip.
When all the sugar has been added, turn up the mixer to high speed and whip the meringue until it holds stiff peaks.
Add a spoonful of the meringue to the cake powder, folding it in gently to lighten the mixture.
Fold in the remaining meringue, and transfer the batter to a 10-inch tube pan.
Bake the cake until golden brown on top, puffed, and springy to the touch (approx. 45 minutes to 1 hour). A toothpick inserted in the thickest part should come out clean.
Remove the cake from the oven and flip it upside-down to cool completely in the pan.