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

In a medium bowl, whisk together the all-purpose flour, baking soda, ground cinnamon, ground nutmeg, and salt.

In a large mixing bowl, beat the softened unsalted butter and brown sugar together until fluffy, about 3-5 minutes.

Mix in the eggs, apple cider, and vanilla extract to the butter-sugar mixture until well combined.

Gradually add the dry ingredients mixture to the wet ingredients, mixing on low speed until just combined.

Using a cookie scoop or two spoons, drop rounded balls of dough onto the prepared baking sheet, spacing them about 2 inches apart.

Bake for 12-15 minutes until the edges are lightly golden and the centers are soft. Allow to cool on the baking sheet for a few minutes before transferring to a wire rack.

In a saucepan, melt the unsalted butter over medium heat, then stir in the brown sugar and heavy cream, bringing to a gentle boil and allowing it to boil for 3-5 minutes.

Remove from heat and stir in the vanilla extract for flavor after the caramel thickens slightly.

Spread a generous amount of the caramel filling on the flat side of one cooled cookie and sandwich it with another cookie.