Heat the apple cider in a saucepan set over high heat until reduced to a 1/2 cup. Add the brown sugar and bring to a boil. Reduce the heat to medium high.
Makes 1 cup of caramel sauce. You’ll need a 1/2 cup for the apples. Reserve 1/2 cup for serving. The caramel sauce can be stored in the refrigerator and gently warmed for serving.