Preheat the oven to 350ºF. Line 12 muffin cups with paper liners (they are too fragile for just cooking spray). Set pan aside.
In the bowl of a mixer, combine the butter and sugar and cream until fluffy. Add the eggs and vanilla and combine.
In a separate bowl, combine the dry ingredients. Add half of the dry ingredients to the mixing bowl and stir to combine. Add the sour cream and buttermilk and mix to combine. Add the rest of the dry ingredients and mix until you have a smooth batter.
In a small bowl, combine the sugar and cinnamon for the topping.
Use an ice cream scooper and plop a scoop of batter into the bowl with the sugar and cinnamon. Gently roll the batter in the sugar and cinnamon. Place the ball into the paper liner.
When you have completed all of the muffins, sprinkle the leftover cinnamon sugar onto the tops of all of the muffins.
Bake the muffins at 350ºF for about 16-18 minutes or until they are golden on top and just baked through.
