Preheat an oven to 425 degrees F (220 degrees C). Cover a cookie sheet with aluminum foil.
Scrub the sweet potatoes, prick them deeply in several places with a fork, and place them on the lined cookie sheet.
Bake the potatoes in the preheated oven until tender, about 45 minutes. Allow them to cool until they can be handled, about 15 minutes. Scoop out the sweet potato flesh into a large bowl and mash well. Stir in orange juice, brown sugar, margarine, orange peel, and cinnamon. If you prefer the sweet potatoes to be very smooth, you can mix them with an electric mixer.
Spread the potatoes in a microwave-safe dish.
Microwave on HIGH until heated through, about 5 minutes.
