In your KitchenAid mixer cream together butter and sugar until light and fluffy.
Add in egg and vanilla and mix until combined.
In a separate bowl combine dry ingredients - flour, baking powder and salt, and mix to combine.
Slowly add flour mixture to butter mixture, mixing well between each addition.
The dough should not be sticky and should not be crumbly. If it is sticky, mix in flour one tablespoon at a time until it becomes not sticky. If the mixture is crumbly, mix in water one teaspoon at a time until the dough holds together.
Mix cinnamon and sugar together and place on a plate.
Measure dough with a 1/4 cup measure and roll into balls. Roll each ball to coat well in the cinnamon sugar mixture and place on a cookie sheet lined with a silpat liner or parchment paper.
Bake at 350?F for 12-15 minutes or until the center is just set.