Peel and cut the sweet potatoes, and boil in a small pot until soft. Drain well and return the potatoes to the pot. Mash, but don’t overdo it; the potatoes should be thick and not too smooth (this way the pie is thicker, and holds together better).

Add the sugar, orange juice, egg, oil, and vanilla. Mix well. Pour into a lightly greased nine-inch round pan. Mix together the topping ingredients and sprinkle on top of the sweet potato mixture. Bake at 350 degrees Celsius/180 degrees Celsius for about half an hour.