This is a delightful drink that makes the classic gin & tonic a bit boring. When Christina suggested we try this, I thought that all that work to make a souped-up gin & tonic wouldn't be worth it. Well, turns out, it was definitely worth it. This drink isn't overwhelming in any one way, but has a layered complexity that heirs on the side of floral yet sweet, but is simultaneously rooted in the dry nature of gin, tonic, and basil. It is a truly delightful combination of flavors and yes, we do mean basil. When I first read to use basil in a cocktail I thought they surely meant mint, but no, we mean basil. So give this one a shot and enjoy.
Start by muddling the blackberries in a small dish. If the blackberries are very ripe & in season, they will be sweet enough that you do not need to add the sugar. If they are not as sweet as you want, add the sugar into the muddle and let sit for 5 minutes. Separately, muddle the 8 basil leaves gently, just enough to release their oils.
Squeeze the contents of 2 of the limes through a strainer and into a cocktail shaker filled with ice. Add the gin and basil into the shaker, and strain the blackberry muddle (make sure it has been at least 5 minutes though so the sugar sets in) into the mixer and shake until ice cold.
Strain the cocktail into 4 separate glasses filled with ice, top off with club soda or tonic water, and garnish with a few fresh blackberries, a basil leaf, and a wedge of lime.