Technically treacle is a generic word in Britain for any syrup made in the process of refining sugar cane, and it can range from very light to very dark. In practice, the lighter syrup which is produced when the sugar cane juice is first boiled, is called light treacle or golden syrup.

The second boiling produces a much darker syrup, which British cooks call treacle (or dark treacle) and we call molasses (or dark molasses). The third boiling produces what we both apparently call blackstrap molasses, which is very dark and somewhat bitter, and which health-food advocates think is heaven on earth, although it is more often used to feed cattle.

If you don't want to track down the real British thing, supermarket-available dark molasses is what you want for your recipes.