Wash sweet potatoes; pat dry. Prick with a fork; place in a shallow baking dish. Bake 40 to 50 minutes or until soft. During the last 10 minutes of baking, prepare sauce.
Melt oil in a medium saucepan. Add brown sugar, salt, orange juice and 1/4 cup water, stirring over low heat until sugar dissolves. Add cranberries; bring to a boil. Reduce heat; simmer, covered, 5 minutes or until cranberries start to pop.
Blend cornflour with 2 tablespoons cold water until smooth. Add mixture into cranberries; cook, stirring constantly, until sauce comes to a boil. Reduce heat and cook 1 to 2 minutes or until mixture is slightly thickened.
Cut each potato lengthways down the centre, about 3/4 the way through; press open from bottom. Place sweet potatoes on a serving platter. Top each with cranberry sauce.