Truffles are from the underground ascomycetes family (tubers) and are reputed for their high prices. It has an odour similar to deep fried walnuts which is extremely pungent to some people, causing a reeling effect. Interestingly, some people are unable to detect the odour of truffles (which is possibly to their advantage!) The white truffle is the most expensive of the family. They are generally served sliced into extremely thin slivers on top of other food .