Preheat your oven to 350°F (175°C).

Prepare the sweet potatoes by peeling and cutting them into chunks.

Boil the sweet potato chunks in a large pot of salted water for about 15-20 minutes, or until tender.

Drain the sweet potatoes and return them to the pot.

Add melted butter, maple syrup, cinnamon, and salt to the sweet potatoes, mashing until smooth.

Pour the sweet potato mixture into a greased baking dish.

In a separate bowl, mix the chopped pecans with a tablespoon of melted butter and a drizzle of maple syrup, if desired.

Spread the pecan mixture evenly over the sweet potato base.

(Optional) Add mini marshmallows on top of the pecan layer.

Bake in the preheated oven for 25-30 minutes, or until heated through and the topping is golden.

Let the casserole cool slightly before serving.