Peel the sweet potatoes and cut them into one inch chunks. Place them in a large pot and cover with salted water. Bring the water to a boil. Reduce the heat and simmer for 10 to 15 minute until tender when pierced with a fork.

Drain the potatoes in a colander and return to the empty pot. Mash the potatoes until they are mostly smooth or run through a potato ricer.

Melt the butter in a small saucepan over medium heat. Let the butter foam and sizzle. Continue to cook for 5 to 8 minutes, swirling the pan occasionally. Watch for brown specks to form at the bottom. The butter will smell nutty when it's ready. Remove it from the heat immediately. Set aside 2 tablespoons for garnish.

Pour the brown butter over the potatoes. Add the heavy cream, brown sugar, salt, cinnamon, and black pepper. Stir everything together until it's combined.

Transfer the potatoes to a serving dish. Drizzle with the reserved brown butter. Garnish with chopped candied pecans or walnuts.