Prepare the sweet potatoes: wash and scrub them gently with a vegetable brush. Pat them dry and prick them a few times on all sides with the tip of a sharp paring knife to vent.
Arrange them on baking sheet. Bake at 400°F for 50-60 minutes or until tender. Remove from the oven and carefully open the foil to vent. Allow them to cool.
Slice the potatoes in half, lengthwise. Scoop out the flesh leaving ¼ to ½ inch on the bottom and all the way around. Place the pieces on a baking sheet lined with a cooling rack.
Brush the inside of each piece lightly with oil. Sprinkle with a pinch of salt. Turn each piece over, lightly brush with oil and sprinkle with a pinch of salt.