2 pounds yams or sweet potatoes (you want to use potatoes that are really orange, also known as yams)
2 tablespoons unsalted butter
1 tablespoon brown sugar or maple syrup
1/2 cup evaporated milk
1/2 teaspoon kosher or sea salt
3 navel oranges
Mini marshmallows, for topping
If you want that s'mores-y color and taste on the marshmallows, broil the orange cups for the last minute of cooking.