Melt the tallow in the top pot of a double boiler or in a bowl that fits over a saucepan. (You should fill the lower part of the double boiler or the saucepan with about 2 inches of water that you have brought to a medium simmer.) Once melted, turn off the heat and add the olive oil to the melted tallow and stir well.
Remove the double boiler or saucepan and fitted bowl and allow the tallow to cool at room temperature for approximately 10 minutes.
Now add the lavender essential oil. Mix well.
Allow the mixture to cool in the refrigerator for 30 minutes or up to 1 hour. Then remove the mixture from the refrigerator and use an electric hand mixer (or stand mixer with the whip attachment) to whip the balm into a cream-like consistency.
Decant the foot cream into a lidded jar, and store in a cool dark place, such as a cabinet or pantry.
The shelf life of the balm is approximately 1 year. Please see "Important Information" in the Recipe Notes section below before using any cream made with tallow balm and essential oils.