In a medium pot, combine the sugar, tapioca starch, salt, and xanthan gum. Mix together using an immersion blender. Bring the mixture to a boil, while blending continuously
Remove the mixture from the heat. Blend the butter and oil into the mixture.
Chill the mixture over an ice bath until cool.
Add the mixture into an ice cream machine. Follow the instructions of the machine and churn until the mixture thickens.
Cover the gelato with plastic wrap.
To ensure a good texture, make sure the plastic wrap is touching the gelato.
