Mix the baking soda, citric acid, cornstarch, and Epsom salt together in a bowl.
Melt the cocoa butter and coconut oil in a double boiler, or a heat-safe bowl set over a pot of simmering water.
Combine the melted cocoa butter and coconut oil with the dry ingredients, mixing well until everything is combined.
Add the essential oil and food coloring, and mix well.
You can then shape the mixture into truffles, and let them dry and harden for a few hours. This recipe should make about 6-8 bath truffles, depending on the size of each truffle.