01 -
Place the sweet potatoes in a large pot and cover with cool water. Add 1 teaspoon salt, bring to a boil, and simmer for 15-18 minutes until very tender.
02 -
Drain the potatoes well and let them sit in the colander for 3-5 minutes so extra steam escapes. This keeps the filling from turning watery.
03 -
Return the potatoes to the warm pot. Add butter, brown sugar, milk, vanilla, cinnamon, nutmeg, and 1/2 teaspoon salt, then mash until creamy.
04 -
Heat the oven to 375 F. Butter a 2-quart baking dish, spread in the sweet potato filling, and smooth the top.
05 -
Bake the uncovered filling for 20-25 minutes, until hot at the edges and warmed through in the center.
06 -
Scatter mini marshmallows over the hot filling and add pecans if using. Bake for 8-10 minutes, until the marshmallows are puffed and golden. Rest 5-10 minutes before serving.