Many revolutions around the sun back, there was a place on Powell, between 82nd and 92nd, called "Spudnuts" or something to that effect, which made donuts with a potato-based dough which were moist and tasty. Anyone know if it is still possible to get a spudnut in this town (or greater metro area)?
Sorry, Dr. Chow. Google tells me that Spudnuts was a chain that has largely faded away. http://spudnutshop.com/ Richland, WA appears to be your closest option.
I occasionally spot a potato doughnut around town. The last great one I had was from the Hideaway Bakery at the Farmers Market in Eugene.
Tasty and Sons does a chocolate potato doughnut. It's not bad - not extremely choclatey, IMHO.