Add the drained yams to a medium size bowl or 4 cup measuring cup.
Slightly mash the yams so they are a little chunky, not smooth. Stir in the melted butter, cinnamon, brown sugar, and vanilla.
Transfer the yam mixture to a casserole dish.
Top with marshmallows and cover the casserole dish loosely with aluminum foil. Bake in preheated 350°F oven for 35 minutes or until the yams are bubbly. Uncover and increase heat to 450 and continue baking until marshmallows are browned.
Notes
For a citrusy twist add about 1-2 tablespoons of frozen orange juice concentrate when adding the vanilla extract.
Easy to prepare the night before and reheat when ready to serve.