Sweet Potato Casserole with Marshmallow and Praline Streusel Topping

For the praline topping:

1 cup flour

2/3 c brown sugar

1/4 c chopped pecans, toasted

1/4 c melted butter

1/4 tsp. cinnamon

Bag mini-marshmallows

4 medium (2 1/2 lbs.) peeled & halved fresh yams    
or 1 large can sweet potatoes

1/2 c sugar

1 1/2 tsp. vanilla

1 large egg white

1 5 oz. can evaporated milk

Preheat oven to 350°. Combine first 5 ingredients together to form a streusel. Set aside.

If using fresh yams boil until just tender, drain & mash. If not, mash a drained can of sweet potatoes. Stir 1 cup streusel, sugar, vanilla, egg white and milk to the mashed sweet potatoes. 

Spread sweet potatoes in a single layer into a greased 2 quart casserole. Alternate rows on top of casserole with remaining streusel and mini marshmallows. Bake at 350 for 45 minutes or until marshmallows are nicely toasted.