I found this recipe on Pioneer Woman's Tasty Kitchen site. Sometimes on weekends friends stop by to visit in the mornings and I love having something to share. It's just as good for dessert as well. :)
Preheat the oven to 350 degrees. Prepare the muffin tin with butter or non-stick baking spray.
Combine butter and sugar with electric mixer until fluffy. Add eggs and vanilla.
In separate bowl combine dry ingredients. Add half of the dry ingredients to the mixing bowl and combine. Add yogurt and buttermilk to mixing bowl and combine. Add the rest of the dry ingredients and mix until batter is smooth.
Combine sugar and cinnamon for topping in small bowl. Scoop batter into bowl with sugar and cinnamon. This can be a fairly large scoop. Gently roll the batter in the cinnamon sugar coating it completely. Place in muffin tin.
Bake for 15-18 minutes or until golden brown on top and a toothpick comes out clean.
TIPS - The original recipe calls for 1 cup (8 oz) sour cream. I never have sour cream on hand so I use greek yogurt. And Fage containers come in 6 oz. so that's what I use. It's perfectly delicious and doesn't seem to be missing anything. Use what you got. :)
Also if you don't have buttermilk on hand you can make your own by using milk and white vinegar or lemon juice. For this recipe you'd use 1/4 milk and 3/4 teaspoon white vinegar or lemon juice. Mix together and let stand for 5 min before adding to the batter.