First – melt your unsalted butter and set aside to cool (so it doesn’t cook your eggs when you add it!) Preheat your oven to 350℉(180℃), and prepare pans with cupcake liners. Set aside.
In a large bowl, whisk together the all purpose flour, baking powder, baking soda and salt. Set aside.
In a medium bowl, whisk together sugar, eggs, vanilla extract, milk and sour cream. Add the cooled melted butter and whisk again until well combined.
Add flour mixture to the wet ingredients and stir until just combined, being careful not to over mix the batter. The batter will be thick.
Divide the batter evenly between the cupcake liners, filling them about 2/3 full. Sprinkle each cupcake with a bit of crushed peppermint candy/candy canes, and swirl them in a bit with a spoon or toothpick.
Bake for 16-20 minutes, or until a toothpick inserted in the center comes out mostly clean.
Allow to cool completely before frosting. (This is an excellent time to make your frosting and filling!)