Preheat oven to 400°.
Grease 14 or 15 regular-sized muffin tins and set aside.
In a large mixing bowl, combine flour, baking powder, baking soda, salt, and granulated sugar.
Set aside.
In a medium-sized mixing bowl, melt butter.
Blend butter, eggs, sour cream, buttermilk or sour milk and vanilla with a whisk until smooth.
Add liquid mixture to dry mixture along with 1 ½ cups chopped Butterfingers.
Stir just until moistened.
Do not overmix!
Fill each prepared muffin tin about ¾ full.
Sprinkle remaining ½ cup chopped Butterfingers evenly over top of each muffin.
Gently press Butterfingers into the tops of the muffin batter so the crumbs adhere to batter.
Bake at 400° for about 18 minutes, or until toothpick inserted in center comes out clean.
Allow muffins to cool.