Prep your glass. Fill a rocks glass with ice to chill it while you build the drink.
If you like, rub a lemon wedge around the rim and dip in cinnamon sugar for a light, festive rim.
Muddle the aromatics. In a shaker, add the apple slices, fresh ginger, and mint leaves. Gently muddle 4–5 times to bruise and release flavor without turning it into mush. You want fragrance and a little juice, not a puree.
Add the liquids. Pour in the cinnamon whiskey, apple cider, lemon juice, and simple syrup.
Taste your cider first; if it’s very sweet, reduce the syrup slightly.
Shake with ice. Add ice to the shaker and shake for 12–15 seconds until the outside is frosty. This chills and slightly dilutes the drink, rounding out the spice.
Strain into glass. Dump the ice from your rocks glass, add fresh ice, and fine-strain the drink over it. Fine-straining keeps out ginger fibers and apple bits for a smooth sip.
Top (optional). For a lighter, spritzy version, add a splash of club soda on top.
Stir once to combine.
Garnish and serve. Add a cinnamon stick, a fresh apple slice, and a lemon wheel. A tiny dusting of ground cinnamon makes it look and smell extra cozy.