In a medium saucepan, bring 1 cup of apple cider to a simmer over medium heat and let it reduce to about ¼ cup.

In a large mixing bowl, cream together ½ cup of softened butter and 1 cup of brown sugar until fluffy. Add 1 egg and 1 teaspoon of vanilla extract, mixing well.

In a separate bowl, whisk together 1¾ cups of flour, 1 teaspoon of baking soda, ½ teaspoon of baking powder, ½ teaspoon of salt, 1 teaspoon of cinnamon, ½ teaspoon of nutmeg, and ¼ teaspoon of cloves.

Gradually add the dry ingredients to the wet mixture, alternating with ½ cup of whole milk until just combined.

Drop rounded tablespoons of batter onto parchment-lined baking sheets, leaving space for spreading.

Preheat your oven to 350°F (175°C) and bake for 10–12 minutes until slightly golden. Allow to cool on baking sheet.

Make the caramel buttercream by creaming ½ cup of butter until smooth, then gradually adding 2 cups of powdered sugar and the cooled apple cider reduction.

Assemble the whoopie pies by spreading filling on one cookie, drizzling with caramel, and topping with another cookie.