Preheat oven to 350°F (177°C) and line a 12-count muffin pan with cupcake liners.
In a medium bowl, whisk together flour, baking soda, baking powder, and salt.
In a large bowl, beat the butter and sugar together until creamy. Add eggs and vanilla; beat until combined.
Mix in the sour cream, then add the dry ingredients and milk alternately, beginning and ending with dry ingredients.
Divide batter evenly among cupcake liners and bake for 18–20 minutes or until a toothpick comes out clean.
Let cool completely before decorating with frosting and Halloween-themed toppings.