Separate eggs; beat egg yolks 1 minute. Add pinch of salt to egg whites; beat until foamy.
Add cream of tartar and continue beating whites until they cling to bottom and sides of bowl, then beat 1 minute longer. Fold beaten egg yolks into egg whites gently but quickly.
Fold in sifted sugar, flour and vanilla. Do not over mix.
Pour batter into pan, spreading evenly from center out with a spoon. Strike pan several times on table to break any air bubbles. Bake in center of oven 18 to 20 minutes or until cake springs back when touched lightly.
Remove from oven, loosen sides and part of bottom quickly with a table knife and lift out of pan by ends of parchment