Chop soap base into small pieces
Following the recommendations on your choice of melt and pour soap, melt the soap base.
Gently stir mustard powder into melted soap base.
Use eye droppers to measure essential oils into melted soap base. Stir well - but gently - to combine
Pour soap into soap molds
Allow soap to fully cool and harden, about 1 hour
Carefully remove soaps from mold. Store in an airtight container, and/or seal in shrink wrap baggies to protect soaps while storing.
If gifting, consider wrapping with ribbon, as pictured