01 -
Preheat the oven to 375°F. Butter a 9x13-inch baking dish or a similar 3-quart casserole dish.
02 -
In a small saucepan over low heat, warm the cream, butter, brown sugar, maple syrup, vanilla, cinnamon, nutmeg, and salt until the butter melts. Do not boil.
03 -
Arrange the sweet potato slices in overlapping rows in the prepared dish. Pour the warm cream mixture evenly over the slices, letting it run between the layers.
04 -
Cover tightly with foil and bake for 35 minutes. Carefully remove the foil and baste the top with some of the cream from the edges of the dish.
05 -
Bake uncovered for 18-22 minutes, until the sweet potatoes are tender when pierced with a thin knife and the cream is bubbling around the edges.
06 -
Scatter the chopped pecans over the top and bake for 8 minutes, just until fragrant.
07 -
Top with mini marshmallows. Broil for 1-3 minutes, watching closely, until the marshmallows are puffed and golden. Let rest 10 minutes before serving.