Heat the oven to 375 F and line a rimmed baking sheet with foil or parchment paper.
Scrub the potatoes, pat dry, and pierce them in several places with a fork or small, sharp knife. Place the potatoes on the prepared baking pan and bake until tender, 1 hour to 1 hour and 20 minutes. The fork or knife should slide in with little resistance.
Place the baked sweet potatoes on a rack and let cool slightly. When the potatoes are cool enough to handle, cut about 1/2 inch off the top and scoop out most of the flesh, leaving a 1/4-inch border for stability.
Put the sweet potato flesh in a medium bowl and add 1/4 cup of brown sugar, 1/2 teaspoon of cinnamon, the nutmeg, salt, pepper, and 4 tablespoons of butter; mash to combine.
Spoon the mashed sweet potato mixture into the shells. Combine the topping ingredients and sprinkle over the stuffed sweet potatoes.
Return the potatoes to the oven and bake for 15 to 20 minutes. Enjoy!