Preheat oven to 350°F.

Mix mashed sweet potatoes, white sugar,eggs, 1/4 cup butter, vanilla and flaked coconut. Place in heat proof 2 quart casserole dish. With fork, mix the brown sugar,flour, pecans and the remaining 1/3 cup of butter. Sprinkle over the top of the potato mixture. Bake at 350 for 30 minutes.