In a shaker, combine vodka, peppermint schnapps, lime juice, and cranberry juice. Shake lightly.
Pour mixture into mug.
Top with ginger beer and stir gently.
Garnish with cranberries and a lime wedge.
Notes
Use peppermint vodka if available. For less sweetness, rim only half the mug. Freeze cranberries for extra chill. Serve immediately for best presentation.