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

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

In a large bowl, beat softened butter and brown sugar until fluffy, then mix in eggs one at a time, followed by apple cider and vanilla until smooth.

Gradually stir the dry ingredients into the wet mixture just until combined; chill for 10 minutes if the batter feels loose.

Scoop rounded balls of dough onto the prepared sheet, leaving 2 inches of space between each.

Bake for 12–15 minutes until edges are golden and centers spring back when gently pressed; cool on a wire rack.

For the caramel, melt butter in a saucepan over medium heat, stir in brown sugar and cream, bring to a gentle boil, and cook for 3–5 minutes until thickened. Remove from heat, stir in vanilla, and let cool to a spreadable consistency.

Spread caramel on the flat side of one cookie and sandwich with another, repeating with the remaining cookies.