Hi Kristie. I am just guessing here but I think the bath bomb part has been made in a cupcake shaped mould and if the whipped soap frosting on top is soft, then it is probably whipped FBB (foaming bath butter) piped on top. What a cool idea!
I think the bath bomb part of it may be pressed directly into the cup (it kinda looks like the bottom of the cup may have that rigid pattern - I've seen plastic cups like that!)
I have made mini bath bombs that I give out as samples in small 2 oz. plastic cups (like you get coleslaw in at a restaurant!) that I pack directly into the cup and they pop right out when they're dry.
Hers are truly gorgeous, aren't they Carebear! I wish I lived in the US so I could afford to order one of everything she makes. My favourite soap of hers is 'Love You Long Time'.....soooo pretty! I often like to browse through her website and etsy store for my creative colour fix