Preheat the oven to 400°F. Pierce the skin of each sweet potato several times with a fork and place on a baking sheet. Bake the sweet potatoes for 45 to 60 minutes or until completely tender, then remove from the oven.
While potatoes are baking, begin heating the oil in a small sauce pot. Add the shallots and ginger and saute over medium-high heat for 2 to 3 minutes. Add the cranberries, orange juice and zest, maple syrup and a pinch each of salt and black pepper. Bring to a boil, reduce the heat and simmer on low for 10 to 15 minutes until the cranberries have broken down and the sauce is thickened. Remove from heat and stir in butter. Taste for salt. Cut the baked sweet potatoes in half lengthwise, spoon warm cranberry sauce over each half and serve.