Rosemary-Concord Shrub

Bring 1 cup Concord grapes, 1/3 cup sugar, and 1/2 cup water to a boil, reduce heat, and simmer until reduced to 1/2 cup, 10 –12 minutes. Strain grape syrup and let cool. For each cocktail, place 4 rosemary leaves, 2 ounces vodka, 1 ounce grape syrup, and 1/2 ounce apple cider vinegar in a cocktail shaker and fill with ice. Cover and shake until shaker is frosty, about 30 seconds. Strain into a rocks glass filled with ice; add 2 –3 ounces club soda.