Melt the butter for the filling in a small bowl. Meanwhile, mix the granulated sugar and cinnamon in another bowl.
Eighth step:
Once the muffins are out of the oven and cooled for a few minutes, brush each muffin with a thin layer of melted butter using a pastry brush.
Step 9:
Sprinkle the cinnamon-sugar mixture generously over the butter layer.
Serve hot and enjoy
