make one 9 x 13-inch baking dish
8 - 9 medium size sweet potatoes (see hints below)
4 Tbs butter
1/4 cup light brown sugar
1/2 tsp ground cinnamon
1/2 tsp ground ginger
1/3 cup orange juice
salt to taste
Mini marshmallows as needed for single layer
Preheat the oven to 400 degrees.
Use a fork to prick 8 - 9 medium size sweet potatoes all over.....and then roast those on a baking tray until they're fork tender.
Depending on the size of the sweet potatoes, they'll take right around one hour to bake.
Peel them when they're cool enough to handle and then mash them up in a large mixing bowl with 4 Tbs butter, 1/4 cup light brown sugar, 1/2 tsp each ground cinnamon and ground ginger.....and, after mashing a bit, add about 1/3 cup orange juice and season with salt to taste.
Transfer that mixture to a well buttered 9 x 13-inch baking dish and top that with a layer of mini marshmallows.
Pop it into 400 degree oven for 20 minutes or so to completely heat all the way through and brown the marshmallows.
If you roast the sweet potatoes ahead of time and cool them down, you may need to bake the mashed sweet potato mixture for 10-15 minutes in the baking dish before adding adding the marshmallow topping. Then continue to bake until hot and top is browned.
Place uncooked sweet potatoes into the 9 x 13-inch baking dish before getting started to get an idea of how many it will take to fill the dish for baking.