Preheat oven to 400°F (200°C). Rinse and dry sweet potatoes; prick with a fork. Bake directly on the oven rack for 50–70 minutes until tender. Allow to cool.
Slice cooled sweet potatoes in half lengthwise and scoop out the flesh into a mixing bowl, leaving a quarter-inch layer in the skins.
Mash sweet potato flesh with softened butter, warmed heavy cream, maple syrup, cinnamon, nutmeg, salt, and pepper until smooth.
In a skillet, sauté diced apple in melted butter for 3–4 minutes; add cranberries and brown sugar, cooking until cranberries pop.
Fold cranberry-apple mixture into the sweet potato base. Stuff each skin with filling.
Bake stuffed potatoes on a baking sheet for 20–25 minutes until heated through.