01 - Preheat oven to 350°F. Line a 12-cup muffin tin with paper liners.
02 - Whisk flour, cocoa powder, baking powder, baking soda, and salt together in a medium bowl.
03 - In a large bowl, beat unsalted butter and granulated sugar until light and fluffy. Incorporate eggs one at a time, then mix in vanilla extract.
04 - Add half the dry mixture to wet ingredients, blend in whole milk and sour cream, then gently fold in the remaining dry mix until just combined.
05 - Divide batter evenly among prepared liners. Bake for 18–20 minutes until a toothpick inserted in the center withdraws clean. Allow cupcakes to cool completely.
06 - Once cooled, use a small knife or cupcake corer to remove a 1-inch section from the center of each cupcake. Fill with mini candy-coated chocolates and return the top.
07 - Beat butter until creamy. Gradually add powdered sugar, unsweetened cocoa powder, milk, and vanilla, beating until mixture is smooth and fluffy.
08 - Generously frost each cupcake, forming a mound to support the witch hat construction.
09 - Melt chocolate chips until smooth. Dip each sugar cone into melted chocolate to coat fully, letting excess drip off. While chocolate is wet, apply sprinkles or colored sugar.
10 - Place one chocolate wafer cookie atop each frosted cupcake. Set a chocolate-dipped cone on each cookie, forming the hat. Wrap a candy belt or licorice strip around the cone base if desired. Allow hats to set until chocolate hardens.