Cakes in Vivid Color was taught by Violet Lin Tran, and covered the basics of color mixing,
choosing a palette, and color "inspiration."
She also showed a few different techniques including quilling, molds, onlays and tiling. Each one of those made up a separate section of the class, and didn't really have anything to do with color theory specifically. I think the idea is to show how to make a few different cakes that you can use color on, but you could easily do the same designs in all white and just have it be about texture. So go nuts, do what you want.
Color aside, this class will show you the basics of using molds and onlays, and shows the basics of quilling for gumpaste and fondant.
The two-toned leaf design that she does is a little Georgia O'Keefey for me, if you get my drift. Maybe it was the color but I'm not a huge fan of that look anyway, it's kind of "heavy" for me, for lack of a better term. I prefer the quilling that gives you a more airy look. I've done fondant in two tones like that and I always roll them out to be thinner, but that's my preference. Seeing how she makes them might inspire you to make your own types of two-toned patterns, though, so have at it.
Overall this class would be good for beginners to color, or for someone looking for some specific designs that can be adapted using different colors. It's a little basic for anyone who has experience mixing colors in fondant already, so if you don't need help with that this might not be what you're looking for in terms of color theory specifically.
If you want a basic color theory class, you could sign up for this one for FREE: 2014 Block of the Month: Craftsy Color Theory. It's a free mini class that's designed for quilters, but color is color, so the tips on combining colors will apply to cake designs.
Click here for my Craftsy pattern shop, which has a bunch of freebies in it: A Cake To Remember On Craftsy
Kara Buntin owns A Cake To Remember LLC, online cake supplies at www.acaketoremember.com and www.acaketoremember.etsy.com