Peel and cut up sweet potatoes. Cover with water and cook until tender.
Beat cooked potatoes. Add sugar, light brown sugar, eggs, salt, margarine and vanilla. Mix well and pour into casserole dish that has been sprayed with Pam.
Bake at 400 until set in pan, approximately 30-40 minutes.
Mix topping ingredients, sprinkle on top of casserole and bake an additional 10 minutes or until browned.