Boil sweet potatoes (peeled, and cut into 1-inch cubes) until fork tender (about 20 minutes).

Preheat the broiler.

Drain the sweet potatoes and add in the unsalted butter, maple syrup, brown sugar, cinnamon and nutmeg. Using a hand mixer, mix the potatoes until smooth.

Spray non-stick cooking spray into an oven-safe dish. Pour the potatoes into the dish. Top with chopped pecans and mini marshmallows. Broil on high for 30 seconds until marshmallows are golden brown. Serve immediately.