Hazelnut oil is a thick, richly aromatic oil made from the roasted nuts. Just a few drops or so can transform a porridge or a salad dressing; in baking and confectionery, too, it imparts a delicious nuttiness. It also goes well on spinach and sweetcorn. I recommend hazelnut oil highly to everyone who loves hazelnuts, and especially anyone who is cutting animal fat out of their diet and therefore liable to miss butter.
A 250ml bottle seems expensive for what it is*, but I use a little most days and it still takes me a couple of months to get through one. The oil should keep for about three months in a cool place.
Hazelnut oil is also used as a carrier oil for aromatherapy massage; it is easily absorbed, and especially good for oily skin. It may be used straight, or diluted with a lighter oil.
* at least in Britain.