Preheat your oven to 355°F.
In a large bowl, mix egg yolks, vegetable oil, water, vanilla, salt, and half of the sugar.
Sift cake flour and baking powder into the mixture in three batches, folding gently after each addition.
In another bowl, beat egg whites and cream of tartar until firm peaks form, gradually adding the remaining sugar.
Gently fold half of the beaten egg whites into the yolk mixture, then fold in the remaining half.
Spray an ungreased chiffon cake pan with water and pour the batter, filling up to 75%.
Bake for 25 to 35 minutes until golden brown and a toothpick comes out clean.
Immediately invert the pan to cool, using a damp towel to speed up the process.
Once cooled, carefully remove the cake from the pan and dust with powdered sugar.
Slice and enjoy your fluffy chiffon cake!