I made some lacto-fermented blackberries last week (extremely easy; you basically mix berries with 2-4% of their weight in salt and keep at room temp in an airtight container for 4-7 days until sour and bubbly). Now this week I get to put the berries to use in a variation on my favorite vodka cocktail: the lemon drop. The salty-funky berries work so well against the tartness of the lemon juice, and the drink is a lovely purple color that stains your mouth and fingers.
To a cocktail shaker half-full with ice, add 1.5 oz vodka, 1 oz lacto-fermented berries, 0.5 oz fresh lemon juice, and 0.25 oz agave or simple syrup. Shake well, then strain into a chilled glass. Enjoy!