Actually, it’s probably quite likely that you’ve had truffles, or perhaps truffle oil. If you want to try some of the best truffles out there then try and find white truffles, preferably from Italy. They are ridiculously expensive and you’ll be hard pushed to find a restaurant that will give you more than a sprinkling of them.
If you really want to splash out then go to your local gourmet food shop and buy white truffles yourself. If they don’t sell them then I’m sure they’d get some in for you.