01 -
Preheat oven to 350°F (175°C). Bring a large pot of water to boil. Cook the diced sweet potatoes until fork-tender. Drain and transfer to a large mixing bowl.
02 -
Add the eggs, white sugar, 4 tablespoons melted butter, vanilla extract, milk, and ground cinnamon to the sweet potatoes. Using an electric hand mixer, blend until smooth and well combined.
03 -
In a small mixing bowl, combine the 3 tablespoons melted butter, brown sugar, all-purpose flour, and chopped pecans. Mix until it forms a loose paste.
04 -
Transfer the sweet potato mixture to a 9x13 baking dish and smooth the top. Evenly spread the brown sugar topping over the sweet potato layer.
05 -
Bake in the oven at 350°F (175°C) for 20-25 minutes, or until the topping is slightly browned.
06 -
Remove the dish from the oven and sprinkle the marshmallows evenly across the top. Return to the oven and bake an additional 5-10 minutes, until the marshmallows are golden and slightly toasted.
07 -
Remove the casserole from the oven and allow to cool slightly. Serve and enjoy.