In a mixing bowl, combine the melted tallow, avocado oil, and essential oil.
1 cup tallow, 1/4 cup avocado oil, 1/2 teaspoon skin-safe essential oil
Place in the fridge to chill 45-60 minutes, or until it's firm through. (It doesn't have to feel rock solid, but it needs to be firm enough to easily whip.)
Use a stand mixer or electric beater with a whisk attachment to whip the body butter. Start slow and gently increase the speed.
Whip until it's light and fluffy and looks similar to a thick icing. This usually takes less than 5 minutes.
Once you're happy with the consistency, scoop into glass jars (or whatever containers you want to store it in).