Preheat oven to 140°

In a large metal or glass mixing bowl, add baking soda, citric acid, and corn starch. Stir to combine.

Add coconut oil, lemon essential oil, and yellow soap colorant. Stir until ingredients are incorporated and the consistency resembles wet sand.

Transfer mixture into muffin tin or silicone molds, filling each mold to the top

Place the silicone mold on a baking sheet and put in preheated oven. Turn oven off and leave door closed for 1 hour.

Remove from oven and immediately press the emoji icing decorations into each individual bath bomb.

Do not remove bath bombs. Air dry bath bombs in mold for 8-12 hours.

Carefully remove the bath bombs out of their molds and store in a mason jar or other airtight glass container.