In a medium saucepan whisk together brown sugar, cornstarch, cinnamon, allspice, ginger, cloves and salt until cornstarch is evenly distributed. Stir in apple cider and apple cider vinegar and set mixture over medium-high heat. Bring to a boil stirring constantly. Allow to boil 1 1/2 minutes while continuously stirring, then remove from heat, stir in butter and allow to cool until warm. Store in refrigerator in an airtight container, rewarm in microwave before serving.
