Peel sweet potatoes and cut into approximately 3/4-inch dice. Place in a 6-quart slow cooker. Add 1 cup water, place lid on and cook on HIGH for 3 hours.
Remove lid and turn slow cooker off. Use a hand-held potato masher to mash the sweet potatoes.
Stir in the brown sugar and butter until the butter is melted. Let cool 5 minutes so that the eggs do not curdle.
While cooling, combine the topping ingredients.
Stir in the milk, vanilla extract, salt and eggs into the crock pot and sprinkle the topping on top. Cover and cook on HIGH for 1 1/2 hours.