What is tom yam paste and where is it available or what is best to use instead? Also what is the substitute for canola oil?
Nigella uses tom yam paste in her Crunchy Salad With Hot And Sour Drressing (from NIGELLA EXPRESS) and Hot And Sour Soup (from NIGELLA BITES). Tom yam (also called tom yum) paste is a paste made from a base of shallot, lemongrass, chillies, galangal (or sometimes ginger), lime leaves and fish sauce. It is used in the Thai hot and sour tom yum soup. It can be found in many major UK supermarkets and also in Asian grocers and on-line. A good substitute is quite difficult but a red Thai curry paste would probably be the closest alternative. However you may need to add a few squeezes of lime juice and a pinch of sugar to help with the balance of hot, spicy, sweet and sour flavours if using a curry paste.
Canola oil is a flavourless vegetable oil made from rapeseed. Any flavourless vegetable oil, such as sunflower or corn oil, could be used as a substitute.