Put the cranberries in a cocktail shaker. With a muddler, mash them. Fill the shaker with ice and add the gin, lemon juice and sour mix. Shake mixture and strain into a highball glass filled with ice. Add cranberry juice and club soda. Garnish with fresh cranberries and a lemon wedge.
Recipe adapted from: Speers, Dana. "Cranberry Gin Fizz." Food & Drink. Holiday 2004.