Prepare Apple Cider: In a medium saucepan, pour in 2 cups of apple cider and set over medium heat. Allow it to simmer for 10–15 minutes, stirring occasionally, until it has reduced to about ½ cup. Let it cool completely before using.

Make Cookie Batter: In a large mixing bowl, cream together ½ cup of softened butter and 1 cup of brown sugar until light and fluffy. Add one room-temperature egg and a splash of vanilla extract, mixing until well combined. Gradually stir in ¼ cup of cooled apple cider reduction until smooth.

Combine Dry Ingredients: In a separate bowl, whisk together 2 cups of all-purpose flour, 1 teaspoon of baking soda, 1 teaspoon of baking powder, ½ teaspoon of salt, and chosen spices. This blend ensures autumn flavor and proper structure.

Mix Dry with Wet: Carefully fold the dry mixture into the wet batter, alternating with ½ cup of whole milk. Start and end with dry ingredients, mixing just until combined.

Bake Cookies: Preheat your oven to 350°F (175°C). Drop rounded tablespoons of batter onto parchment-lined sheets. Bake for 10–12 minutes until set, then cool on a wire rack.

Prepare Buttercream Filling: Beat together ½ cup of softened butter and 2 cups of powdered sugar until smooth. Gradually add remaining ¼ cup of apple cider reduction, vanilla extract, and a pinch of salt until creamy.

Assemble Whoopie Pies: Pipe a generous swirl of buttercream on one flat side of the cookies, drizzle with caramel, then top with another cookie. Repeat until all cookies are filled.