ISO: Sweet Sourdough Starter w/ Potato Flakes

I'm looking for a recipe for a sweet sourdough starter using instant mashed potato flakes to feed the starter. This recipe was originally from a dear family friend from Marshall, N.C. She thought the starter and recipe came from the local farm bureau/co-op. It was also referred to as a friendship bread because you passed along a cup of the starter each week to a friend. It made a very heavy, dense but slightly sweet loaf of bread and it did not contain any fruits or nuts but I definitely remember feeding with instant mashed potato flakes and possibly sugar. Thank You to anyone who might have a similar recipe or know where I can track down the starter. Laura in Michigan.