Using the same recipe outlined above, make a white cake batter. Mix the dry ingredients in one bowl and the wet in another, then combine the two and beat until they are well incorporated. Put equal amounts of batter into six separate bowls. Use food coloring to dye the bowls of batter red, orange, yellow, green, blue and purple. Use a small measuring cup to scoop some red batter into a a cake pan. Use a different cup to scoop some yellow batter into the same pan. The two colors can touch, but don't pour one directly on top of another. Continue scooping different-colored batters into the cake pan until you've used half the batter from all of the bowls. Repeat with the second cake pan and the remaining batter. Place the two cake pans in the oven and bake them for about 20 minutes, or until a toothpick or cake tester comes out clean. When the cakes are done, let them cool completely before assembling the cake. Beat the powdered sugar, butter, cream and vanilla together until the frosting becomes light and fluffy. Use a serrated knife to cut off the rounded tops of the two cakes. Place one layer on the cake plate or stand you're using to serve the cake. Scoop frosting onto the cake and use an offset spatula or a frosting knife to spread it across the cake's surface. Place the second cake layer on top of the frosting. Finish frosting the cake by covering the top and sides. Add edible glitter, birthday candles, or other cake decorations as the final touch. The cake is now ready to serve.

TL;DR in Chinese:
烤箱预热到177摄氏度。 制作面糊。 将面糊等量分在六个碗里，然后用色素把面糊分别染成红色、黄色、橙色、绿色、蓝色和紫色。 把面糊分别倒入两个抹了油的烤盘里。 分层烤蛋糕。 制作糖霜。 组装蛋糕。 装饰蛋糕。