Preheat oven to 375°F. Line a large baking sheet with parchment paper.
Using a fork, prick the sweet potato a few times on each side to create heat vents. Place the sweet potatoes on the prepared baking sheet. Bake for 70-80 minutes, or until the potatoes are soft.
Allow the potatoes to cool for 15-20 minutes, or until they are cool enough to handle.
Scoop out the inside of each sweet potato (discard the skins) and place the contents into the bowl of a food processor.
Add eggs, brown sugar, salt, pepper, vanilla, nutmeg, cinnamon, and cayenne. Blend until smooth.
Spray an 11x7-inch baking dish with nonstick cooking spray. Pour the potato mixture into the prepared baking dish.
Bake for 20-25 minutes, or until sweet potatoes are set. While sweet potatoes are baking, prepare the marshmallow meringue.