Chiffon cake

Sift the cake flour into a large bowl.

Preheat the oven to 325 with the rack in the lowest position.

Sift in the sugar and baking powder and whisk briefly.

Leave the tube pan clean and ungreased: no butter, flour or spray, so the batter can climb the sticky sides.

Separate the eggs, each white into a small bowl first and then into the clean stand-mixer bowl, yolks into a medium bowl.

Add the water, vegetable oil and vanilla to the yolks and whisk until smooth, pale and frothy.

Mix the yolk mixture into the dry ingredients until just combined, without working the gluten; the batter will be thick. Set aside.

Add the cream of tartar to the whites, start the mixer low, then raise gradually to high and whip about 6 minutes to stiff peaks.

Work quickly: fold about a quarter of the whites into the batter to lighten it.

Fold in the rest, scraping the bottom with the spatula and cutting in, until no dark and light streaks remain.

Spoon the batter into the tube pan, keeping it off the walls; run a small knife through to pop large air bubbles rather than tapping the pan.

Bake at 325 Fahrenheit for about an hour, until a skewer comes out clean and the cake springs back.

Cool completely upside down on the pan's feet, overnight if wanted, or it will collapse.

Free the sides with a palette knife or spatula, working carefully past the rivets, then free the top and turn out.

Dust with powdered sugar and slice; serve plain or with whipped cream, berries or frosting.