Measure root beer layer ingredients into a small pot, and orange layer ingredients into another.
Whisking often, bring the two mixtures to a boil. Once boiling, reduce heat to low and simmer just until sugar is dissolved and all carbonation has come out of the mix.
Remove both from the heat, allow to cool to room temperature.
Once cooled, poor root beer later into popsicle molds, until about ⅓ full.
Freeze popsicle mold until solid. Chill orange layer and remaining root beer layer mixtures until ready to use.
Pour orange layer over frozen root beer layer, until about ⅔ full.
Affix lid and popsicle sticks, freeze until solid.
Carefully remove mold lid, top-up each popsicle cavity with root beer layer.
Freeze until solid.
Carefully unmold - I'll usually run a bit of hot water over the outside of the mold cavities - and enjoy!