This one doesn't have rivels, just an old favorite, from the 1927 Fannie Farmer cookbook. Quantities are approximate since my book's in storage.
Peel and cook taters with salt. Drain, add whole milk, and heat gently to keep from scorching. Add a pinch of celery seed, or to taste, half an onion minced fine and cooked in butter till transparent, and some pepper. Get a large ball of soft butter and work flour into it until it will not hold any more. Add this to the soup to thicken it. Continue heating until soup is thick, adjust seasonings, add butter if needed for flavor. Serve with good bread and, if you like, grated cheese.
Alternately, you can make this with chicken broth and pieces of chicken. Surprisingly, I prefer the plainer soup. It does not work as well with low-fat milk, and not at all with powdered or canned.