Lightly prick the potatoes a few times with a fork and place the potatoes on a foil lined baking sheet. Bake at 400 degrees, until knife tender (when they begin to ooze sugary syrup) about 1 hour and 15 minutes. Remove from the oven and let sit until cool enough to handle.

Scoop out the flesh into a mixing bowl. Add white sugar, salt, butter, vanilla and milk. Mix with an electric or stand mixer until smooth and creamy.

Transfer mashed sweet potatoes to a greased baking dish.

Topping: I add the flour and cold butter to my food processor and pulse until I get crumbs. Then I stir in the chopped pecans. Or you can mix the flour and butter or margarine by hand using a fork and a knife until crumbly, then stir in the chopped pecans and sprinkle over potatoes.

Bake at 350 degrees for 40-45 minutes.

NOTE: You can make the potatoes ahead of time, transfer to a greased casserole dish, cover and refrigerate. You can also make the topping ahead and refrigerate in a air tight container. When ready to bake, sprinkle topping over potatoes and put casserole dish in oven. Then turn oven to 350 degrees (can't put a cold dish in a hot oven, it could crack). Add an additional 5 minutes to baking time.