I took white vanilla frosting and mixed my own colors with food coloring. Then I placed the colors in their respective ziploc sandwich bags, cut off the tip and squeezed away! I also used leftover white frosting in a ziploc cut to a tiny hole for the "sesame seeds" because I didn't want actual sesame seeds on my dessert!
TIP: When cutting the tip of a ziplock, start tiny and work your way up. You can always make the hole bigger, but not smaller!
Also, I used brownie for the center instead of chocolate cake, as is mentioned on Bakerella.com