Whisk together the baking soda, citric acid, cornstarch, and Epsom salts.
In a second bowl, combine the melted coconut oil, essential oil blend, and alcohol together, mixing well.
Add liquid ingredients 1 tsp at a time to the dry ingredients, mixing them together slowly so as not to start the fizzy reaction.
Add in the red mica powder and mix well. If you want more color, add some additional mica powder in 1 tsp increments.
Dust the bottom of one side of one of the bath bomb molds with cornstarch. The sprinkle side tends to come out on its own, so do not bother to dust that side with cornstarch.
Place about 1 tsp of sprinkles in the non-dusted side of the bath bomb mold.
Immediately pack the bath bomb mold with the sprinkles overly full of the red mixture. You want there to be an excess mixture to help bond the two sides of the mold together. Repeat with the other side of the bath bomb mold.
Press the two sides of the bath bomb mold together, grinding and pressing them to force the two together.
Allow the bath bombs to rest in the mold for up to 24 hours before gently tapping the side of the mold to release the bombs.
To make the gold accents, combine the gold mica powder and the alcohol and paint dots onto the bath bomb, as desired.
Use your bath bombs immediately or store them in an airtight container until you’re ready to use them!