Preparation Steps

• Preheat the oven to 350°F (175°C) and line a 12-cup muffin tin with cupcake liners.
• If reducing apple cider, simmer 1 cup apple cider in a small saucepan over medium heat until reduced to about 1/2 cup; cool slightly. Otherwise measure 0.5 cup cider.
• In a medium bowl, whisk together the flour, baking powder, baking soda, salt, cinnamon, and nutmeg; set aside.
• In a large bowl, cream the 0.5 cup softened butter with the granulated sugar and 0.5 cup light brown sugar until light and fluffy, about 2 to 3 minutes.
• Add the eggs one at a time, mixing well after each addition, then beat in the vanilla.
• With the mixer on low, add one-third of the dry ingredients, then half the sour cream and apple cider, then another third of the dry ingredients. Repeat until just combined, scraping the bowl as needed — do not overmix.
• Divide the batter evenly among the 12 liners, filling each about two-thirds full. Bake for 16 to 18 minutes, or until a toothpick inserted into the center comes out clean.
• Allow cupcakes to cool in the pan for 5 minutes, then transfer to a wire rack to cool completely before frosting.
• For the buttercream, beat 1.0 cup softened butter until creamy. In a small saucepan, gently heat the 1.0 cup dark brown sugar with 2 tablespoons heavy cream just until the sugar dissolves and the mixture is glossy; cool slightly and add to the butter.
• Gradually add the powdered sugar, one cup at a time, mixing on low until combined. Stir in 1 teaspoon cinnamon and 0.25 teaspoon salt. Add additional cream if needed to reach a spreadable consistency and beat until light and fluffy.
• Pipe or spread the buttercream onto the cooled cupcakes. Optionally, sprinkle with a pinch of cinnamon or a drizzle of reduced apple cider.
• Store cupcakes in an airtight container at room temperature for up to 2 days, or refrigerate up to 5 days. Bring to room temperature before serving.