Preheat oven to 350 º F (177 º C). Line a 12 standard-size muffin tin with cupcake liners.
In an electric mixer, beat the butter and brown sugar with a paddle attachment on medium speed until light and fluffy.
Add eggs one at a time, allowing each egg to blend into the butter mixture before adding the next. Blend in vanilla extract and mashed sweet potatoes.
In a separate medium bowl, mix together flour, baking powder, baking soda, salt, apple pie spice, ginger, cloves, and orange peel. Add half the flour mixture to the batter mixture, beating on low speed just until incorporated.
Beat in the buttermilk and the remaining flour mixture. Stir in both the chopped pecans and maple syrup.
Scoop batter with a standard-size ice cream scooper into prepared cupcake pan (fill to 3/4 full) and bake cupcakes in preheated oven for about 18-20 minutes or until a toothpick inserted in the center of a cupcake comes out clean. Cool on a rack.
For the Toasted Marshmallow Topping: Create a small mound of mini marshmallows (about 7-10 marshmallows) on top of each cupcake.
If you have a crème brûlée torch, you can use that to brown the topping instead of your oven's broiler. If you don't have a torch, preheat oven broiler and place topped marshmallow cupcakes on a baking sheet.
Brown the marshmallows under the broiler for about 30-60 seconds or until the tops of the marshmallows are golden brown, watching carefully to prevent the marshmallows from burning.
Remove from oven and place baking sheet on a rack to cool slightly. Use a metal spatula to transfer cupcakes to a platter. Enjoy!