Pour Seagrams Extra Dry Gin, blackberry syrup, triple sec, lemon juice, and soda water into a cocktail shaker. Stir to combine. DO NOT shake!
Fill a collins glass with ice.
Pour the cocktail into the glass and garnish with a lemon slice.
You can make this drink for a crowd too! In a 2.5-quart pitcher, combine 2.5 cups Seagrams Extra Dry Gin, 1 cup blackberry syrup, 1/2 cup triple sec, 1/2 cup fresh lemon juice, and 4 cups soda water. Stir to combine. Add lemon slices to the pitcher. Pour into glasses over ice to serve.