Preheat your oven to 350°F (175°C). Grease and flour a 9-inch round cake pan to prevent sticking.

In a medium saucepan, bring the apple cider to a boil over medium heat. Reduce the heat and let it simmer until it reduces to about 1/2 cup, approximately 10-15 minutes. This concentrates the flavor.

In a large mixing bowl, cream together the softened butter and granulated sugar using a whisk or electric mixer until light and fluffy, about 3-5 minutes. This incorporates air into the mixture, helping the cake to rise.

Add the eggs one at a time, mixing well after each addition. Then stir in the vanilla extract.

In a separate bowl, whisk together the sifted flour, baking powder, baking soda, ground cinnamon, and salt.

Gradually add the dry ingredients to the wet mixture, alternating with the reduced apple cider. Start and end with the dry ingredients. Mix until just combined; do not overmix.

Pour the batter into the prepared cake pan and smooth the top with a spatula.

Bake in the preheated oven for 40-45 minutes, or until a toothpick inserted into the center comes out clean. Allow the cake to cool in the pan for 10 minutes before transferring it to a cooling rack.

In a small bowl, whisk together the sifted powdered sugar, apple cider, and ground cinnamon until smooth. Adjust the consistency by adding more cider or powdered sugar as needed.

Once the cake has cooled completely, drizzle the glaze over the top, allowing it to drip down the sides for a beautiful presentation.