I found sunchokes for sale at our local grocery store, King Soopers; they are about 2" long, very knobby, and creamy white color; I don't know what variety they are. The produce department is clueless as to what these are. They sell for $1.99 per pound; they get them from "Frieda" in Los Alamitos, CA.
I bought them because they are recommended by Dr. Steven Gundry in his new book, "The Plant Paradox" as a very good prebiotic. I have been washing them and then coating them with olive oil and onion powder and baking/roasting them at 430 degrees for an hour. We think they are our new substitute for potatoes. Since we have arthritis, we have to avoid all nightshade vegetables such as potatoes, tomatoes, eggplant, etc.