Make the simple syrup. Add the sugar and water to a small saucepan over medium heat. Stir until sugar is completely dissolved.Allow to cool, then pour into a glass jar and seal tightly with a lid. Simple syrup will keep, refrigerated, for about one month.
In a cocktail shaker, add the blackberries and simple syrup. Muddle the blackberries until the begin to break up. Pour in the tequila, blackberry liquor, lemon juice, and a handful of ice. Place the lid on the cocktail shaker and shake vigorously for 30 seconds.
Strain with a fine mesh strainer into a chilled cocktail glass, top with ginger beer and ice if desired. Drink and enjoy!