How to Make It
Whisk together honey, vinegar, and pepper in a bowl. Add 2 cups blackberries; let stand 45 minutes, mashing occasionally. Add gin; chill 15 minutes. Transfer mixture to a small pitcher. Stir in soda water and ice. Rub lemon rind strips around rims of 4 rocks glasses. Pour cocktail into glasses. Add rind to each glass. Garnish, if desired.