Sweet Potato Souffle

3 cups cooked, peeled, and whipped sweet potatoes
1/2 cup margarine softened
1 cup sugar
2 eggs
1 tsp vanilla

Topping:
1/2 cup margarine softened
1/3 cup flour
1 cup light brown sugar
1 cup chopped pecans

Preheat oven to 350 degrees.  Combine first 5 ingredients and pour into 9x9 greased casserole.  Prepare topping and spoon over top.  Bake for 30 minutes.