Peel potatoes (leave whole) and boil until tender. Add a pat of butter in water to keep pan from sticking. Remove potatoes from water an let drain for 5 minutes. Arrange sliced potatoes (sliced not too thin) in a large baking dish 10x14-1/2 inch. You can make two layers.
Measure sugar in sauce pan and add one large can evaporated milk. Heat well until sugar is dissolved. Pour over sweet potatoes. Add (cut up) margarine or butter and corn syrup. Cook in a 350F oven for approximately an hour or until thick syrup forms in pan. Remove from oven. Add chopped pecans and return to oven for another 15 minutes (to roast pecans). Add marshmallows last and bake until golden brown.
Sprinkle sweetened coconut flakes on potatoes before adding marshmallows.
Cajun Country -- New Iberia, Louisiana