Heat the oven to 350°F (175°C, 170° for fan ovens).
Grease and flour or line two 2 pound loaf pans (should be about 9 x 5 inches or 23 x 13 centimeters).
In a large bowl, mix together the sugar, milk, oil, vanilla, sweet potatoes and eggs until well blended.
Sift together the flour, baking soda, baking powder, salt, cinnamon and nutmeg.
Add the dry ingredients to the sweet potato mixture and stir just until moistened.
Stir in the cranberries or raisins and pecans. (Or divide the batter evenly between two bowls after stirring in the pecans. Stir half a cup of dried cranberries into one bowl and half a cup of raisins or sultanas into the other.)
Put the batter in the loaf pans, dividing evenly if you have not already divided the mixture.
Bake 50 to 60 minutes or until a skewer or toothpick inserted in the centre comes out clean.
Cool for 20 minutes before removing from the pans.
Loosen the sides of the loaves from the pans (if you use liners you won’t have to do this) and place right side up on a cooling rack.
Cool for about 2 hours before slicing - if you can wait that long!
The loaves will keep tightly wrapped at room temperature for up to 4 to 5 days.