Hi, I don't have any experience myself, but would be really interested in learning more about them myself. Do you know if they grow in Washington as well? I live south of Olympia and we have a lot of prairie with oak trees in the area - I know truffles grow underneath oak trees and we have the same species of oak (Q. garryana) that's found in Oregon growing here in SW Washington.
From the following publication, 'A feasibility study' : "Although native northwest species are found from northern California to southern British Columbia, they fruit most abundantly in Oregon and are widely known as “Oregon Truffles.”"
Search scroogle for Oregon Culinary Truffles: An Emergent Industry for Forestry, Agriculture & Culinary Toursim A feasibility study by: David Pilz, Charles Lefevre, Leslie Scott & James Julian
In Pursuit of Northwest Truffles by Kris Wetherbee
Solar Station Construction Plans by Ben Peterson -- ebook