Chipotle-Cherry Barbecue Sauce

Ingredients

• 1 pound fresh or frozen cherries
• 1/2 cup sugar, or as needed, plus more if needed to taste
• 1/3 cup water
• 1/4 cup red wine vinegar
• 1/2 cup port wine
• The grated zest and juice of 1 lemon
• 1 cup rich duck stock or chicken stock
• 1 cinnamon stick
• 1 to 2 teaspoons minced canned chipotle chile
• 1 1/2 teaspoons cornstarch
• 1 tablespoon kirsch or brandy
• 1 tablespoon unsalted butter
• Salt
• freshly ground black pepper