A pudding of flour and water, often with raisins or molasses, boiled in a cloth bag. Careful though: give someone a duff and it means a kick in the backside.
Duff
Where the word comes from
The Dictionary of Newfoundland English has two entries. The first is the pudding, with an example from 1856 of a ship's menu with duff. The second is a blow, especially a kick in the backside.
