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

Whisk together the flour, baking soda, cinnamon, nutmeg, and salt in a bowl and set aside.

Cream the softened butter and brown sugar together until light and fluffy, about 3-5 minutes.

Add the egg, apple cider, and vanilla to the creamed mixture and mix until smooth.

Gradually stir in the dry ingredients until just combined to avoid overmixing.

Scoop rounded balls of cookie dough onto the prepared baking sheets, spaced 2 inches apart.

Bake for 12-15 minutes or until edges are golden and centers appear soft. Let cool.

Prepare the caramel filling by melting butter, brown sugar, and cream in a saucepan, then boil for 3-5 minutes.

Add vanilla to the caramel mixture and remove from heat.

Once cooled, spread caramel filling between two cookies to assemble the whoopie pies.