What an adorable mold! I saw someone's video (Soap Queen maybe?) where they used a similar type of mold, poured in a small amount dark colored batter, swirled it around the inside until it was thick enough to stick then let it harden. Then they used a small detail tool to scrape out some of the batter and poured the rest. Now I think of it, it was probably M&P but it might work with CP. I'll see if I can find it.....
Here it is and yep, it's M&P. I bet you can do something similar though!
[ame]https://www.youtube.com/watch?v=9duEvRSNrdM[/ame]