In a large bowl, mix together your dry ingredients. If there are any clumps, you can push the powder through a sifter or break up them up with your fingers. Citric acid has a tendency to take off nail polish, so wear gloves to protect your manicure.

Add 1 ounce of melted coconut oil, 12 mL of Strawberry Fragrance Oil, 6 mL of polysorbate 80, and about 1/4 teaspoon of mica. Mix all the ingredients together with your hands.

Separate a small amount of your mixture and set it to the side. This will be your "frosting". Add an additional 1/4 teaspoon of mica to create a darker blue color. 

Test the consistency of the bath bomb mixture. The perfect consistency for molding is similar to wet sand and holds its shape when squeezed. If it’s too dry, use one hand to spritz the mixture with witch hazel and one to mix. Continue spritzing until the mixture holds its shape.

Start by scooping and pressing your frosting layer into the bottom of the mold. Don't cover the entire mold with frosting, or you won't be able to see the light blue donut underneath. 

Fill the rest of each mold with the lighter blue mixture. Pack tightly to ensure your bath bombs are firm after unmolding. 

Let the bath bombs harden for 4-6 hours, or overnight. Then, carefully unmold your bath bombs. 

In a small container, disperse 1/2 tsp of mica in about 1/4 tsp. 99% isopropyl alcohol to create "paint". The paint should be thin enough to spread but saturated enough to leave a strong color.

Using a fine-tipped paint brush, add sprinkles to the top of your bath bomb. We chose to do small circular sprinkles to mimic the look of blueberries, but you can do rectangular sprinkles, stripes, hearts, whatever you'd like! 

Allow the bath bombs to dry for several hours. To use, place in a hot bath and enjoy!