Apple Cider - Any type of apple cider will work here. Apple cider will have the most flavor, but you can use apple juice if apple cider isn’t available. Be sure to follow the instructions to reduce the apple cider down and let it cool completely before using it in the recipe. The step to reduce the cider is important because it gives you the most concentrated flavor in the muffins. It can take about 30 minutes and needs to cool completely, but can be done up to a week ahead of time.