Preheat your oven to 350°F (175°C).
Peel and chop the sweet potatoes into large chunks.
Boil the sweet potatoes in a large pot of salted water until tender, about 15-20 minutes.
Drain and mash the sweet potatoes in a large mixing bowl.
Mix in sugar, milk, eggs, vanilla, cinnamon, and salt until well combined.
Pour the sweet potato mixture into a greased baking dish.
(Optional) Layer chopped pecans or mini marshmallows on top.
Bake in the preheated oven for 25 to 30 minutes or until heated through and lightly set.
Serve warm, and enjoy your Southern Sweet Potato Casserole!