How to Make It
Combine cider, 1/2 cup chopped apple, 1 cinnamon stick, allspice and ginger in a small saucepan; bring to a boil. Remove from heat and let stand 1 hour. Strain and chill at least 2 hours. Stir in gin and vinegar.
Divide ginger beer evenly among 4, ice-filled copper mugs. Add 1/2 of cider mixture to an ice-filled cocktail shaker; shake vigorously until thoroughly chilled, about 15 seconds. Strain evenly into 2 mugs and garnish with apple slices and cinnamon sticks. Repeat with remaining cider mixture, apple slices and cinnamon.