Here's one recipe:
½ cup butter
2 cups flour
¾ cup sugar
2 tsp baking powder
½ cup milk or water
1 cup raisins
Combine dry ingredients and add milk and egg. Place in
cloth bag and boil for one hour in pot of water. (usually in with the boiled dinner)
Ingredients can also be steamed in a pudding mild.
To make a plain duff follow same recipe but omit raisins.
I must say, I know my M-I-L never used eggs, and I don't think she added sugar either. I haven't been able to reproduce her recipe.