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.

Combine the 1/2 c. sugar and 2 tsp. cinnamon and set aside.

Place a small amount of batter in tin, add desired amount of the cinnamon & sugar mixture (we like a lot ☺, probably a 1 tsp. or so), then add another small amount of the batter on top. Sprinkle lightly with the cinnamon mixture.

Bake at 350° for 15 minutes, or until done.