@kitchengoddess: Is it essential to fry off or toast all spices when cooking with them? Or can some be added later?
Jamie Oliver: This is a really good question. It's quite nice to heat or toast most powdered spices, to a lesser or greater degree. It does bring them back to life and you can achieve colour and a sort of a nuttiness and toastiness for sure (although some finer powders like turmeric and chili powder don't benefit from this). At the same time, like when using fresh, dried, powdered and smoked chilies, using spices in different ways often gives you light and shade. So sometimes it's nice to sprinkle similar spices over the top of the dish once you've served it up. But generally speaking, heating or toasting does accentuate the natural oils and flavour of most spices.