Peel sweet potatoes and cut into large pieces. Place in water and boil to cook will tender. Preheat oven to 350°F while potatoes cook.
While potatoes cook, prepare the topping. Mix the chopped pecans, brown sugar, and bacon pieces together. Set aside.
Remove potatoes from pot and place in a large mixing bowl.
Add butter, milk, cinnamon, maple syrup, salt, and pepper. Using a hand mixer on high speed whip the sweet potatoes till smooth and fluffy. Add the eggs and mix to incorporate into the sweet potatoes.
Lightly spray an 8x8 baking dish with cooking spray. Pour potatoes in to the baking dish. Top with pecan mixture.
Place in oven and bake for 25 minutes. After 25 minutes add the marshmallows and bake for an additional 10 minutes.
Remove from oven and serve.