1. Preheat your oven to 325°F (or 165°C) to ensure even baking.
2. In a large mixing bowl, sift together cake flour, half of the granulated sugar, baking powder, and salt to create a smooth, lump-free mixture.
3. In a separate bowl, whisk egg yolks with vegetable oil, water, and vanilla extract until the mixture becomes pale and frothy for optimal blending.
4. Gradually combine the egg yolk mixture with the dry ingredients, stirring until a smooth batter forms.
5. In a stand mixer, beat egg whites and cream of tartar on medium speed until foamy, then slowly add the remaining sugar and continue whipping until stiff peaks form.
6. Gently fold the whipped egg whites into the batter using a spatula with a cutting motion to retain the batter’s airy texture.
7. Pour the batter into an ungreased tube pan, spread it evenly, and gently tap the pan to release air bubbles trapped in the batter.
8. Bake the cake in the preheated oven for 50 to 60 minutes. Perform a toothpick test to verify the cake is baked thoroughly, ensuring the toothpick comes out clean.
9. Once baked, invert the tube pan onto a wire rack to cool completely upside down, which maintains the cake’s height and fluffy texture.
10. Carefully run a butter knife along the sides of the pan to loosen the cake. Remove it gently by lifting it upwards and serve.