Special equipment: a copper mule glass
Put a handful of cranberries in a small bowl and cover with some Simple Syrup. Let soak until slightly softened, about 1 hour. Chill a copper mule glass.
Put the vodka, orange juice, cranberry juice and 1/2 ounce Simple Syrup into a cocktail shaker filled with large ice cubes. Shake vigorously and reopen. Add the ginger beer and tumble-roll back and forth one time to mix in the ginger beer. Strain into the chilled copper mule glass. Garnish with 3 cranberries and serve.
Combine the sugar and 1 cup water in a small saucepan and bring to a boil. Cook, stirring, until the sugar dissolves. Remove from the heat and let cool completely. Keep covered in the refrigerator up to 1 month.