Add the mashed sweet potatoes, sugar, eggs, butter, vanilla, and salt to a mixing bowl and stir well to combine.
Spread mixture into a greased 2 quart baking dish.
For the topping
Stir together the brown sugar, pecans, butter, and flour until well combined.
Spoon pecan mixture over the sweet potato casserole and smooth out to cover the entire casserole.
Bake for 30 minutes. Remove from oven and let set for 20 minutes before serving.
To make mashed sweet potatoes, you can either used canned or fresh sweet potatoes.If using canned sweet potatoes, drain all liquid from the can and mash immediately or microwave for 2 minutes to warm up and then mash. They mash easier when warm.If using fresh sweet potatoes, peel and cube the sweet potatoes and boil for 20-30 minutes or until fork tender and easily mashed.