Nigella's recipes often suggest using "flavourless vegetable oil". What oil should I buy please?
Flavourless vegetable oil is usually specified in baking recipes and also for frying. It is usually used for frying as most vegetable oils can tolerate fairly high heats (usually up to around 200c) without burning and also they will not impart their own flavour to foods. Olive oil has a distict flavour which could affect in the finished dish. In baking the flavourless oils are also favoured as again they will not affect the flavour of the finished cake.
We often give the term "flavourless vegetable oil" as the specific oils available will vary according to country. Corn oil, groundnut (peanut) oil and sunflower oil are all flavourless oils that can be used for baking and frying. For rapeseed (canola) oil you need to buy the cheaper expeller pressed version of this oil. In the UK this is often labelled as just "vegetable oil". You can buy cold pressed rapeseed oil and safflower oil but these are usually more expensive than the other oils and the rapeseed oil has a slightly peppery flavour. We would suggest using the cold pressed oils in the same way as olive oil, in dressings and to finish dishes.
Do not use groundnut (peanut) oil if cooking for people with nut allergies.