Back in another lifetime there were Spudnuts, a legendary franchise chain that produced wonderful potato-based doughnuts. People in and near Sacramento are very fortunate to have one of the remaining Spudnuts shops in the city. Of course it's not part of the original franchise (which is long gone), but this shop gets its potato-based mix from a place in Utah according to the woman at the shop. She'll tell you which varieties are made the Spudnut way and which are not (you'll have to ask). I stopped there today and had a glazed raised (the standard; start with that) and an apple fritter. The "Spudnut difference" is more obvious with the glazed raised. I'm not great at descriptions of food but it's firmer and still soft, more substantial, I think less sweet, and has a noticeably different flavor that I really like. The apple fritter is probably the best donut-shop apple fritter I've ever had, less of a belly bomb than others. It's been too long for me to have a reliable taste memory of the original ones, so I can't say if these are the same, but these are close enough and very good.
Here are a few pics: http://ruthvenphotos.com/spudnuts-sac
If you want to know more about Spudnuts, here's information that I culled from the web:
I can't add a place link, so here is the info:
2445 Arden Way
Sacramento, CA 95825