Let eggs stand at room temperature for 30 minutes. In a small bowl, soak poppy seeds in hot water for 15 minutes.
In a large bowl, combine the flour, sugar, baking powder, salt and baking soda. In a small bowl, whisk the egg yolks, oil, vanilla and poppy seeds with water. Add to dry ingredients; beat until well blended.
In another large bowl, beat egg whites and cream of tartar until stiff peaks form. Fold into batter.
Pour into an ungreased 10-in. tube pan. Cut through batter with a knife to remove air pockets. Bake at 350° for 50-55 minutes or until cake springs back when lightly touched.
Immediately invert pan; cool completely, about 1 hour. Run a knife around side and center tube of pan. Remove cake to a serving plate.