Mom's Sweet Potato Casserole

3 cups mashed potatoes (or 2 LARGE cans yams)
1/2 cup brown sugar, packed
1/4 cup butter (half a stick) - room temp
1 tsp vanilla
2 beaten eggs - room temp
1/3 cup milk

combine all ingredients and put into a 9x13 dish - preheat oven to 350 degrees

Topping :

3/4 cup brown sugar - packed
1/2 cup flour
1/3 cup butter - room temp (5 1/3 tbsp)
1 cup chopped pecans

Mix together and top sweet potatoes

Bake at 350 degrees for 25-30 minutes.