Add the cranberry juice, vodka, cranberry simple syrup, lime juice and a handful of ice to a copper mug.
Using a bar spoon, stir until condensation builds on the glass, about 15-20 seconds. This ensures our drink is nice and chilled.
Pour in ginger beer. Gently stir with the cranberry mixture to combine. If possible, chill the ginger beer before adding to the drink to keep the mug cold.
If desired, garnish with cranberries and the rosemary sprig. Sip and embrace that festive feeling. Enjoy!