Please can you advise if the olive oil in the Chocolate Olive Oil Mousse can be replaced with vegetable oil or even rapeseed oil?
Nigella's Chocolate Olive Oil Mousse (from AT MY TABLE) is a smooth and delicately flavoured mousse. The oil helps to give the mousse a soft, melt-in-the-mouth texture. But it is the olive oil particularly that gives the mousse its unique flavour.
It may be technically possible to use a vegetable oil but most vegetable oils are flavourless and will leave the mousse tasting flat and less rounded, so it is not an option we would follow. Cold pressed rapeseed oil can be peppery and assertive, rather than smooth, and we suspect that this will affect the flavour of the mousse, so it is not something we would particularly recommend. If you can't use olive oil we would suggest perhaps trying NIgella's Instant Chocolate Mousse instead, or for a slightly different white chocolate option try the White Chocolate And Passionfruit Mousse.