In a large bowl combine baking soda, citric acid, cornstarch, epsom salt and dried lavender.
Combine almond oil, water, and essential oil in a separate small bowl.
Whisk the wet mixture into the dry - slowly. You can test to see if the mix holds together by gently pressing a handful together. If the mixture doesn’t hold lightly, use a spray bottle with water to add more moisture to the mixture. Be careful not to add too much water, or the mixture will fizz and not form correctly in the mold.
Once it’s the right consistency, press the mixture into your mold - really packing it in firmly. Allow to dry overnight before carefully removing from the mold.
Enjoy in a warm bath!