Sourdough Apple Cider Muffins

Preheat oven to 375°F. Grease a 12-count muffin tin with cooking spray or line with muffin liners.
Pour the apple cider into a small saucepan and bring it to a gentle simmer over medium heat. Let it cook, stirring every so often, until it’s reduced to about ¼ cup (60g/ml) and slightly darker in color. This will take roughly 20 minutes. Pour it into a heat-safe bowl or a glass measuring cup and let it cool to room temperature before using
In a medium bowl, whisk together the cooled apple cider, sourdough discard, melted butter, light brown sugar, egg, applesauce, and grated apples.
In a separate, larger bowl, whisk together the all-purpose flour, baking powder, baking soda, salt, and apple pie spice.
Pour the wet ingredients into the dry ingredients and mix together until fully incorporated.
Scoop the muffin batter evenly into the 12 muffin wells, filling each one about ⅔ full. Bake for 22-25 minutes or until a toothpick in the center of the muffins comes out clean. Let the muffins cool for 5-10 minutes before transferring them to a wire rack to cool completely.
In a small bowl, microwave 2 tablespoons of butter in short intervals until fully melted. In a separate bowl, combine the granulated sugar and ground cinnamon. Dip the tops of each muffin into the butter and then dip into the sugar-cinnamon mixture.