Preheat the oven to 350°F (175°C).
Boil sweet potatoes until tender, about 15-20 minutes.
Drain and mash the sweet potatoes in a large bowl.
Stir in maple syrup, melted butter, milk, eggs, vanilla, cinnamon, and salt.
Transfer the mixture to a greased 9x13 inch baking dish.
In a separate bowl, combine graham cracker crumbs and chopped pecans.
Sprinkle the graham cracker and pecan mixture evenly over the sweet potatoes.
Bake for 30-35 minutes, or until heated through and golden brown on top.
Remove from oven and let cool for a few minutes before serving.