Whip the tallow on its own first with a hand mixer until it starts to soften and loosen up.
Slowly drizzle in the carrier oil while continuing to whip, until fully incorporated.
Add the nutmeg and whip to combine.
Add the essential oils one at a time, whipping briefly between each.
Add the brown mica powder and whip until the color is evenly distributed, with no streaks to your liking.
Continue whipping for a few minutes total, until light and fluffy, scraping down the sides as needed.
Spoon into a jar. It'll firm up a bit more as it fully sets at room temperature.