Cream the butter and sugar together until soft about 3 to 5 minutes. Add in the vanilla. Add in the eggs one at a time and mix until each is incorporated.
In a separate bowl, mix together the flour, baking soda, baking powder, cream of tarter, and nutmeg.
Add the flour mixture and the sour cream alternately to the egg-butter mixture in the additions. Start with the flour and end with the flour. Scrape the bowl occasionally.
Using an ice cream scoop, scoop out muffin batter one at a time and drop into a shallow bowl filled with cinnamon sugar mixture. Roll the muffin around in the mixture until it is completely covered with the cinnamon sugar mixture. place muffin in muffin tin. Depending on size of your muffin tin you should have 12 to 14 muffins. Bake 20-22 minutes at 350 degrees or until they are golden brown