2 oz of dry vermouth
2 tsp of creme de cassis (or blackcurrant-flavored liqueur)
1 oz of Lemon Juice
4 oz of Tonic water
1/2 oz of Gin
Pour the vermouth, gin, creme de cassis and lemon juice into a cocktail shaker half-filled with ice cubes, and shake well. Strain into a collins glass almost filled with ice cubes, and top with tonic water. Stir well, garnish with a lemon wedge, and serve.