Preheat your oven to 350°F (175°C).

In a small saucepan, reduce the apple cider over medium heat until it becomes thick and syrupy, about 10-15 minutes. Once reduced, let it cool.

In a bowl, whisk together the flour, baking powder, baking soda, cinnamon, nutmeg, and salt.

In another bowl, cream the softened butter and brown sugar together until the mixture is light and fluffy.

Beat in the egg and vanilla extract, then mix in the cooled apple cider until well combined.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix.

Drop tablespoon-sized balls of dough onto a lined baking sheet, making sure to leave space between each dough ball.

Bake for 10-12 minutes or until the edges are golden brown.

Let the cookies cool for a few minutes on the baking sheet, then fill half of the cookies with caramel sauce. Top with another cookie to form whoopie pies.