01 - Set the oven temperature to 400°F.
02 - Pierce each sweet potato several times with a fork and arrange them on a foil- or parchment-lined baking sheet.
03 - Bake for 50 to 60 minutes until tender when tested with a knife.
04 - Remove from the oven and let cool slightly. Slice each potato lengthwise without cutting all the way through.
05 - Fluff the inside of each sweet potato with a fork, then drizzle with melted butter. Sprinkle brown sugar, cinnamon, nutmeg, and salt evenly over them.
06 - Top each potato with a layer of mini marshmallows.
07 - Return to the oven and bake for 5 to 7 minutes until marshmallows turn golden and toasted. Monitor closely to avoid burning.
08 - Serve warm immediately.