In a large bowl beat egg whites until foamy. Add in the cream of tartar and beat until stiff peaks form.
In another bowl beat egg yolks until smooth.
Fold in 1/4 of the egg whites into the egg yolk batter to lighten it up. Then gently fold the rest of the egg whites.
Pour the batter into a 10" tube pan and bake for 55-60 minutes or until a toothpick comes out clean.