" I pointed at some bright-orange little bells that looked lethal to me. "Are they all edible?"
"I would not be serving them to the guests if they weren't," he said. "These chanterelles, they have exquisite taste. These are straw mushrooms." He pointed to a cluster of thin white stalks. "These we call cèpe. These big ones are trumpet royale. And these, morels- although you must never pick these for yourself. The false morels look very similar and can be fatal. Try the chanterelles. You must cook some for your queen. She will approve."
"But that thing you were going to buy. How does one cook that?" It looked like a dirty ball of earth.
He rolled his eyes. "That, chérie, is worth more per gram than gold. It is a truffle. You do not have truffles?"
"No."
"Then let me instruct you. The truffle is a fungus that grows on the roots of certain oak trees. Under the soil, you understand. They can only be located by specially trained dogs, oh, and by pigs if they can get at them. They have a deliciously different flavor. We make the truffle oil for cooking, or we use a small amount to raise the quality of the dish. "

― Rhys Bowen , Above the Bay of Angels