Muddle 2-3 large apple slices in a 12 to 16-ounce jar or cocktail shaker.
Add 1/4 cup of booze (whiskey, vodka, rum, and tequila are all great), the juice of 1 lemon, 1 teaspoon maple syrup, a tiny pinch of cinnamon, and a dash of bitters to the jar. Fill with ice and shake until cold.
If you like a really boozy cocktail, drink as is. If you want something a bit lighter, fill the remaining space with club soda.