Stem ginger in syrup, also called preserved ginger, is a wonderful ingredient. You can use it in sweet or savoury dishes and it keeps almost indefinitely in the fridge. Opies is a good brand - it's widely available in delicatessens and supermarkets, or order online at b-opie.com - they also do a good spread of recipes, sweet and savoury, that use it.
Although the big, knobbly hands of fresh ginger are called 'root' ginger, stem ginger is exactly the same stuff, just peeled and cooked slowly in syrup. The difference in name is just convention - and, anyway, neither is strictly accurate because ginger is technically neither root nor stem, but a rhizome (something between the two).
Finely diced, sweet-hot stem ginger is fantastic in cakes, biscuits, sauces and trifles. You can trickle the syrup alone over a fruit cake or ice cream, and both ginger and syrup can be added judiciously to sweet-and-sour dishes such as stir-fries or sticky ribs.
