Add all of the ingredients (vodka, apple liqueur, lime juice, and simple syrup) to a cocktail shaker or mason jar filled with ice.
2 ounces vodka, 1½ ounces sour apple liqueur, ½ ounce freshly squeezed lime juice, ½ ounce simple syrup
Shake until completely chilled, about 30 seconds.
Strain into a martini or coupe glass and garnish with a slice of green apple.
(Optional) To make this martini extra spooky, add a ½-inch piece of dry ice to the cocktail. Allow the cocktail to finish smoking before consuming.
Notes
You can replace the vodka with a similar clear spirit, such as gin, white rum, tequila, or sake. Any of these will change the flavor slightly.
For a lower-alcohol cocktail, swap the sour apple liqueur for apple juice or apple cider.
For a different take, swap the sour apple liqueur for apple brandy.
You can swap the lime juice for lemon juice, cointreau, or triple sec instead, if you prefer.
To make your own simple syrup, combine 1 cup sugar and 1 cup water in a saucepan, boil for 1 minute, then cool and refrigerate!
Dry Ice Disclaimer: Always handle dry ice with caution– use temperature-proof gloves and never handle dry ice with your bare hands. Store dry ice in an area with plenty of ventilation. Do not eat dry ice. Consult a safety data sheet for complete safety protocols.
Storage: Store a poison apple martini in an airtight container in the refrigerator for up to 2 days.