Creating these irresistible Apple Cider Whoopie Pies is simple if you follow these easy steps:

1. Preheat the Oven: Begin by preheating your oven to 350°F (175°C). Line two baking sheets with parchment paper.
2. Mix the Dry Ingredients: In a large bowl, whisk together the flour, baking soda, baking powder, cinnamon, nutmeg, and salt until combined.
3. Cream the Butter and Sugar: In another bowl, cream the softened butter and granulated sugar together until light and fluffy.
4. Add Egg and Vanilla: Beat in the egg and vanilla extract until well combined.
5. Incorporate Apple Cider: Gradually add the apple cider to the butter mixture, mixing well.
6. Combine Mixtures: Slowly add the dry ingredients to the wet ingredients, stirring until just combined to avoid overmixing.
7. Scoop the Batter: Use a cookie scoop or tablespoon to drop even amounts of batter onto the prepared baking sheets, leaving space between each dollop.
8. Bake: Bake in the preheated oven for 15-20 minutes, or until the edges are lightly golden and a toothpick inserted in the center comes out clean.
9. Cool: Remove the trays from the oven and allow the cookies to cool on the baking sheets for about 10 minutes before transferring them to wire racks to cool completely.
10. Make the Filling: In a separate bowl, beat the softened butter, powdered sugar, vanilla extract, and apple cider until smooth and creamy.
11. Assemble the Whoopie Pies: Once the cookies have cooled, spread a generous amount of the filling onto the flat side of half of the cookies, and sandwich them with the other halves.