In a large bowl combine brown sugar, eggs, vanilla, milk, butter and salt. Whisk to combine.
Boil sweet potatoes in cold water, just covering, until fork tender. Drain well.
Toss sweet potatoes in the butter mixture. If you are going to puree your potatoes, you can do it at this stage or you can press the potatoes through a ricer after draining.
Pour into a 1 ½ – 2 quart casserole dish.
Mix all the topping ingredients together in a medium bowl and sprinkle over the top.
Bake 30-40 minutes until bubbling.
Notes
I did like this casserole better when it was prepared right before baking, but an overnight stay in the refrigerator wasn’t the end of the world. If you do want to prepare it ahead of time, make the filling and refrigerate or freeze that, then prepare the topping right before baking.I halved this recipe for the dish that you see in the photos.