Pour apple cider into an ice cube tray and freeze for at least 3 hours or overnight.
In a high-speed blender, combine the frozen cider cubes, bourbon (or rum), cinnamon, nutmeg, vanilla, and a splash of apple cider. Blend until smooth and slushy.
Add more cider for a lighter texture or an extra cube or two for a thicker, frosty drink.
Rim glasses with cinnamon sugar, pour in your slushie, and garnish with apple slices and a cinnamon stick.