Begin by peeling and chopping your sweet potatoes into small chunks. Place them in a pot of boiling water and cook until fork-tender, about 15-20 minutes.

Drain the cooked sweet potatoes and transfer them to a mixing bowl. Use a potato masher or fork to mash them until creamy.

In the same bowl, add the sugar, milk, melted butter, eggs, vanilla extract, and cinnamon. Stir until everything is well combined and smooth.

Preheat your oven to 350°F (175°C). Pour the sweet potato mixture into a greased baking dish.

Evenly distribute the mini marshmallows over the sweet potato mixture. In a small bowl, combine the brown sugar and chopped pecans, and sprinkle it over the marshmallows.

Place the casserole in the preheated oven and bake for 25-30 minutes, or until the marshmallows are golden brown and the casserole is heated through.

Remove from the oven and let it cool for a few minutes before serving. Enjoy this delicious layered delight!