Combine the tallow, coconut oil, castor oil, apricot kernel oil, hazelnut oil, and avocado oil in a large stainless steel pot on medium heat until melted. Remove from heat and cool until oils are around 90 degrees Fahrenheit.
Weigh goat milk and freeze. Weigh lye in zip close bag and set aside until goat milk is ready. When goat milk is frozen, take it and the lye outside to combine. Wear gloves, charcoal mask, and goggles and pour the lye into the goat milk and stir until dissolved. Cool until around 90 degrees Fahrenheit.
When both oils and lye milk is at the proper temperatures, pour the lye milk into the oils and blend with a stick blender until light trace.
When soap is at light trace, add the essential oil or combination of essential oils that you desire and blend.
Pour soap into the prepared mold and cover.
After 24 hours, remove from the mold and cut if necessary. Cure for 3-6 weeks until the soap is hard.