Preheat the oven to 425°F. Line a cupcake pan and lightly grease the liners with non-stick spray. This will ensure that they peel off the muffins nicely.
Dip the top of the muffins into the melted butter, then roll in the cinnamon-sugar.
You can substitute whole wheat flour instead of regular flour. I made them with whole wheat flour as well and it will work with this recipe.