Add about 2 tbsp of granulated sugar and 1 tsp of cinnamon to a small plate and mix well (keep in mind, most of the sugar will not adhere to the rim).
To make your cinnamon sugar rim, first dip the rim of your favorite glass (I like using a stemless wine glass or small mason jar) in water. Next, slowly roll the rim of the glass around in the cinnamon sugar mixture until you have your desired amount of rim.
Next, fill your glass with ice cubes. Then, pour in your apple cider and cranberry seltzer water. (Note: you can use a cocktail shaker, but make sure to shake super gently because of the carbonation).
Stir with a cinnamon stick, garnish with freshly sliced apples and enjoy.
Notes
For a lower sugar mocktail, use 1/4 cup apple cider and 3/4 cup seltzer water.