For the cake: grease and line two of the round pans, set aside. In a bowl, whisk together cake mix, vegetable oil, water, egg yolks, ube powder and ube flavoring until smooth. In another bowl, whisk egg whites until if forms stiff peaks, fold whipped eggwhites into uber cake batter. Pour into the prepared pans. Bake in the preheated oven for 20-25 minutes or until cooked. Place also in the refrigerator to cool and set.