I just love this drink in any form. It's so refreshing. Blackberries and gin is one of my favorite combinations. Possibly more than gin and cucumber! I have mixed this and left it as a drink with ice cubes and macerated fruit. I also love to blend and drink it as a slushie on a hot day.
Combine the blackberries and sugar in a medium bowl and let sit at room temperature. Combine the gin, club soda and lime juice in the blender and blend just to combine. When ready to serve, add the blackberries and ice to the blender and pulse to desired consistency. Blend more if you like a smoother texture. Pour into glasses and serve immediately.