Preheat oven to 350 degrees. Grease a muffin tin; set aside.
In a large bowl, cream together the butter and sugar until fluffy. Add the egg and mix until well combined.
Sift together the dry ingredients. Add alternately the dry ingredients with the milk, beginning and ending with the dry ingredients. Fill the muffin cups 2/3 full (should fill about 10 of the cups). Bake for 20-25 minutes or until golden brown.
While puffs bake, mix together the remaining sugar and cinnamon in a shallow bowl.
Upon removing from the oven, immediately roll puffs in the butter, then then cinnamon-sugar mixture. Best served hot, but will keep for up to 3 days in an airtight container.