Preheat oven to 350° and spray mini muffin tins with non-stick spray and set aside.
Mix flour, sugar, baking powder, salt, and cinnamon in a medium bowl until combined.
In a measuring cup melt butter. Add in milk, egg, and vanilla. Mix until combined.
Pour wet ingredients into the dry ingredient. Mix until all is incorporated.
Fill each muffin tin to about 2/3 way full.
Bake for 12-15 minutes or until golden. Remove from oven and let sit in the pan for 5 min. Remove from the pan and let muffins cool completely on drying rack.
While muffins are cooling, melt 6 TBSP butter in a small bowl.
In a separate small bowl mix the sugar and cinnamon.
Once muffins are all the way cool, dip the tops of each muffin in the butter and then in the cinnamon/sugar mix as the topping.