1. Cream the butter and sugar together

2. Add the eggs, grated sweet potato and beat the mixture well

3. Add the grated rind of lemon and orange

4. Add the ginger, mace and the cinnamon

5. Beat the custard well again

6. Bake the custard in a well-buttered baking dish in a moderate oven of 350F (180C) for 1 hour

List of ingredients required:

2/3 cup butter
1 cup brown or white sugar
2 cups grated raw sweet potato
2 beaten eggs
Grated rind of 1 orange
Grated rind of 1/ 2 lemon
1/2 teaspoon mace
1/2 teaspoon ginger
A dash of cinnamon