If you decide to line the rims of the glasses with cinnamon, first dip the rim of your glass in maple syrup. Then, roll it around in the cinnamon. Leave them stored upside down until ready to serve.
In a large pitcher combine the apple cider with the ground ginger and vanilla. Mix and taste to adjust to your flavor preference. I would also add in 1 cinnamon stick, and 1-2 star anise to intensify the flavor. You can store this in the fridge for up to 2 days in advance.
When ready to serve: add some ice into your cups. Along with a few apple slices.
Pour in the drink. You can either use all of it or fill up as much of the glass with as you like. Then, top with all of the seltzer or as much of it as you like.
Garnish with a few more apple slices, a cinnamon stick, and star anise if desired. Enjoy.