Preparation

THE SHRUB:

Place the blackberries in a nonmetal bowl or pitcher; add the vinegar, sugar, and salt. Stir well to combine and cover with plastic wrap or a lid; refrigerate for 1 to 2 days. Transfer the berry mixture into a nonreactive saucepan and place over medium heat. When the mixture comes to a simmer, let cook for about 10 minutes, skimming any foam that may rise to the surface. Strain the cooked berry mixture into a fine-mesh sieve over a heatproof storage container. Press the blackberries against the sieve to extract all liquid. Discard the solids. Store the shrub, covered and refrigerated, for up to 6 weeks. Makes about 1 quart of concentrate.

THE BLACK JACK COCKTAIL: 

Combine the brandy, lemon juice, orange juice, and blackberry shrub in a cock- tail shaker with ice and shake well until cold and combined. Strain over cocktail glasses filled with crushed ice. Garnish with fresh mint.