Preheat the oven to 350º F. Whisk together the flour, baking powder, salt, nutmeg, and cinnamon.
In a separate large bowl, whisk together the oil, sugar, egg and milk.
Add the flour mixture to the oil and milk mixture and stir just until combined.
Coat a standard 12-cup muffin pan well with nonstick cooking spray and divide the batter evenly among the cups.
Bake for 15 to 18 minutes, until a toothpick inserted into the center of one muffin comes out clean.
Run a knife around the sides of each of the muffins and shake them out of the pan while still hot. Place them on a wire rack while you assemble your toppings.
In a small, shallow bowl, melt the butter.
In another small, shallow bowl, combine the sugar and cinnamon.
Dip each muffin first in the butter, then into the cinnamon-sugar, swirling to coat all sides. Let cool for a few minutes on a wire rack so that the butter and sugar can harden slightly before serving.