Preheat oven to 375°

Bring potatoes, or yams, to boil.

Reduce heat and simmer until tender (15 min).

Drain and place potatoes in a bowl.

Add brown sugar, butter, salt, and vanilla.

Mash potatoes.

Place mixture into casserole dish (coated with cooking spray).

Top evenly with marshmallows.

Bake at 375° for 25 minutes or until golden brown.