In a small saucepan, combine the 8 tablespoons butter, brown sugar, heavy cream, cane syrup, cinnamon, salt, nutmeg, ginger, and allspice. Bring to a boil over medium heat, and stir until the sugar dissolves. Remove from the heat and set aside.

Shingle a single layer of sweet potatoes in the bottom of a multi-cooker bowl, and pour 1/4 cup of the butter-sugar mixture on top. Continue to shingle layers of the potatoes and the sugar mixture until you have used it all. Close the lid of the multi-cooker, set it to the “steam” program, and cook for 1 hour.

In a small saucepan, heat the remaining 1 tablespoon butter, and when it has melted, add the marshmallows and cook over low heat until melted. Add the pecans and toss well.

Allow the potatoes to cool slightly. Remove the bowl of the multi-cooker from the machine. Invert a plate or platter over the top of the bowl, and carefully but quickly invert the bowl and plate together. The candied sweet potatoes should come out in one piece onto the plate, resembling a potato galette. Pour the marshmallow-pecan mixture over the top of the sweet potatoes, and serve immediately.

Note: Note : Whole nuts or halves are best for toasting and can be chopped easily once they have cooled.