Step 1

Boil sweet potatoes in large pot of water until tender, around 20-25 minutes.

Step 2

Preheat the oven to 350 degrees.

Step 3

Drain the sweet potatoes and mash in a large bowl. Add vanilla, brown sugar, nutmeg, salt and orange juice or orange-flavored liqueur and mix well.

Step 4

Grease a 9x11 baking dish. Layer half of the sweet potato mixture evenly in the baking dish.

Step 5

Sprinkle marshmallows over the top. Add remaining sweet potato mixture on top of marshmallows and spread evenly using an off-set spatula or knife.

Step 6

Sprinkle yellow cake mix evenly over the top of sweet potato mixture. Pour melted butter or margarine evenly over the top of the cake mix.

Step 7

Bake for 60 minutes. Serve warm or at room temperature.