Split the vanilla pod and scrape out the seeds with a small, sharp knife.
"Mash" the vanilla seeds together with a bit of the sugar on the cutting board to separate the seeds.
Mix xanthan gum with the homemade vanilla sugar.
Pour the milk into a blender and start it at the lowest setting.
While blending, add the vanilla/xanthan gum mixture - continue blending slowly, do not increase the speed.
Peel the banana and slice it.
Add banana and cinnamon and continue blending until the drink is smooth.
Finally, add ice cubes and blend until the ice is crushed and the milkshake has the right consistency.
Serve in a tall glass with a straw and optionally extra ice.