Carefully cut your soap base into 1 inch cubes and add 8 to a microwave-safe glass measuring cup.
Melt soap base in microwave. Start with 30 seconds on high. Stir with a wooden craft stick, and then heat in 10 second increments (stirring between each interval) until soap base is melted. (This only took 40 seconds TOTAL for mine 30+10)
Mix in 1 Tablespoon "add-ins" : coffee grounds, dried herbs, dried citrus peels, dried lavender, oats, etc. This recipe used 1/2 Tablespoon dried lavender and 1/2 Tablespoon oats, both ground with a coffee grinder.
Add 30 drops of essential oil and stir. For this recipe I used 30 drops of lavender essential oil.
Pour mixture into a silicone soap mold.
Allow soap to cool and harden at room temperature, then pop them out of the silicone mold and they are ready to use.