• In a blender, combine the blackberries and sugar. Blend until liquefied. Strain into a container through a fine mesh sieve, discarding any large pulp or seeds that remain.
• At this point, you can combine all ingredients except the Topo Chico in a pitcher and pour over ice, topping with the sparkling water. If you're making individual drinks, portion out into a shaker, shake well, and pour over ice. Top with Topo Chico, a wedge of lime, and any leftover berries.

Notes

• The ratios of gin to lime juice to blackberry puree is up to your individual taste, so add more or less of whichever ingredients you choose.