In a medium bowl, whisk together flour, cinnamon, nutmeg, baking soda, and salt and set aside.
In a large bowl, combine the sugar, sweet potato puree, and eggs. Beat until smooth.
Mix in the oil, maple syrup, and vanilla extract.
Slowly add the flour mixture to the wet ingredients and mix until fully incorporated. Do not overmix or your cupcakes will develop a gummy texture.
Fill cupcake liners 3/4 full.
Bake for 20-25 minutes or until a toothpick inserted into the center of a cupcake comes out clean.
Remove cupcakes from tins and set on a cooling rack to cool to room temperature.
Set cooled cupcakes on a cookie sheet lined with a silicone mat.
Use a pastry brush to brush the tops of the cupcakes with corn syrup – this will make the marshmallows stick.
Stick mini marshmallows all over the tops of the cupcakes.
Place the cupcakes under a broiler for about three minutes or until the marshmallows are lightly browned. They go from browned to burnt very quickly. It helps to keep the oven door open during broiling so you can watch them very closely.
While the marshmallows are still hot, gently push together any that may have moved during broiling.
Canned sweet potato puree should be easy to find in most grocery stores. If you have your own homemade sweet potato puree in the house or leftover mashed sweet potatoes, you can also use those. If your mashed sweet potatoes have already been sweetened, you'll want to reduce the amount of sugar in the recipe.
If you like other spices, you can add them as well. Try adding ginger, allspice, or cloves.
I suggest using pure maple syrup, but if you only have maple-flavored syrup in the house, that will work as well.
If you don't want to use corn syrup, you can try attaching the marshmallows with honey (it doesn't work quite as well). Or, you can frost the cupcakes and place the marshmallows on top of the frosting.
The cupcakes will keep at room temperature for three days. They can also be frozen (without the marshmallows) and will last for months in the freezer.