- Grease and flour muffin tins. 
- Mix flour, baking powder, baking soda, and salt; set aside. 
- Pour the 1 c. sugar into a large bowl, then add the melted butter. 
- Add eggs, vanilla, and sour cream, and mix well. 
- Stir in the flour mixture. 
- Gently fold in the blueberries.  (Make sure if you're using frozen berries that you've rinsed them well and patted them dry first.)  
- Fill muffin cups 2/3 full,  then sprinkle a teaspoon of sugar on top of each one. 
- Bake at 350° for 15 minutes, or until done.