Heat Tolerant Bath Bomb Icing

[urboogyman]

Hey all! My doughnut-shaped bath bombs are some of my best sellers. I put an icing on them made of cocoa butter and baking soda, topped with sprinkles. That's great during the cool months, but it's melting at my farmer's markets in the heat of the summer.

Does anyone have an idea for increasing the melting point, while still allowing it to melt or dissipate in bath water?