This was a true test cake. It was my first time to: 1) make a rainbow cake, 2) use pudding as a filling, and 3) make black icing. The rainbow colors were too light - any suggestions? I filled the cake with instant box pudding, iced it, and immediately put it in the fridge to set....big mistake. The icing would sweat each time I took it out to try and smooth it. I ended up having to smooth it with a spatula as best as I could. For the black icing I used chocolate BC, but it still tasted bitter after adding the coloring. BC only.