In a small saucepan over medium heat, add the apple cider. Cook for 20 minutes, stirring frequently, until it is reduced to about ¼ cup. Set aside to cool completely.

In a bowl of a stand mixer with the paddle attachment, add the unsalted butter and light brown sugar. Mix on medium speed until light and fluffy. Add the egg, vanilla extract, and the cooled, reduced apple cider. Mix until combined and set aside.

In a separate large bowl, combine the all-purpose flour, apple pie spice, baking soda, and kosher salt.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Preheat the oven to 350°F (175°C) and line two large baking sheets with parchment paper.

In a small bowl, add sugar and apple pie spice. Whisk to combine and set aside.

Use a 2-tablespoon cookie scoop to scoop out the dough.

Roll each dough ball in the sugar mixture, coating all sides completely.

Place the coated dough balls on the lined baking sheets, spacing them 2 inches apart.

Bake for 8-10 minutes or until the edges are set and lightly browned. The centers will still be soft.

Cool the cookies on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.

While the cookies are cooling, prepare the glaze. In a small bowl, add the confectioners' sugar and 2-3 tablespoons of apple cider. Whisk to combine. Add more apple cider as needed to reach your desired consistency.

Drizzle the glaze over the cooled cookies. Serve.