Mom's Sweet Potato Casserole

3 C mashed sweet potatoes
1/2 C sugar
1/2 C milk
2 eggs
1 teaspoon vanilla
1/2 stick margarine (room temperature is easiest)
Combine these ingredients in baking dish

Top with:
 1 C chopped pecans (sometimes I use walnuts)
 1 C  coconut
 1/2 C brown sugar
 1/2 C flour1/2 C margarine
 Sprinkle over the top 
 Bake at 375 for 30 min.