Preheat your oven to 350F. Grease and flour the bottom of one (8×3-inch) round pan and set aside. In a large bowl, combine cake flour with a half cup of sugar, baking powder and salt, then sift together and whisk until combined. Set aside.
In this recipe we need to use fresh eggs as possible. Separate egg yolks from the whites and set aside. Add egg yolks, oil, milk, ube extract and violet food coloring, then mix thoroughly until batter becomes smooth.
In a separate bowl, whisk egg whites with the remaining sugar until stiff peaks form. Fold the whites into the batter mixture in three additions.
Pour the batter into a prepared pan, if you want your cake a bit tall use 8×3-inch round pan and if you prefer a wider cake use a 9×2-inch round pan. Bake at 350F for about 20-25 minutes or until inserted toothpick in the center comes out clean. Fire off, let your cake cool down on a wire rack for a couple minutes and invert the pan to cool completely.