Step 1: Preheat your oven to 350°F (175°C). Line a 12-cup muffin pan with paper liners.
Step 2: In a medium bowl, whisk together the flour, baking powder, baking soda, cinnamon, nutmeg, ginger, and salt. Set aside.
Step 3: In a large bowl, using an electric mixer, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy (about 2-3 minutes).
Step 4: Beat in the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
Step 5: Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk, beginning and ending with the dry ingredients. Mix until just combined; do not overmix.
Step 6: Gently fold in the finely diced apples.
Step 7: Divide the batter evenly among the 12 prepared cupcake liners, filling each about two-thirds full.
Step 8: Bake for 20-22 minutes, or until a toothpick inserted into the center of a cupcake comes out clean.
Step 9: Remove the cupcakes from the oven and let them cool in the muffin pan for a few minutes before transferring them to a wire rack to cool completely. Cupcakes must be fully cool before frosting.
Step 10: While cupcakes cool, prepare the Caramel Buttercream. In a large bowl, beat the softened butter until creamy. Gradually add the sifted powdered sugar, beating until smooth.
Step 11: Beat in the 1/2 cup caramel sauce, vanilla extract, and pinch of salt. Add milk or cream one tablespoon at a time until the frosting reaches your desired consistency.
Step 12: Once cupcakes are completely cool, pipe or spread the caramel buttercream onto each cupcake. Drizzle with extra caramel sauce before serving. Enjoy!