Gently melt the carnauba and cocoa butter of tallow in a double boiler. You can also use a glass bowl on top of a pot filled partway with water.
Once melted, whisk your pigment of choice into the hot wax.
Quickly pour the melted crayon mixture into your crayon molds. You can use silicone molds in different shapes (like lego or stars). Muffin tins or silicone ice cube trays can also work.
Let cool completely before removing, about 20 minutes.
Repeat steps 1-4 to make other colors as desired.
Notes
After you’ve poured your crayons, place your pot back in the double boiler so that the thin layer of remaining wax heats up. When it’s hot, wipe it out with paper towels for easy cleanup.