When we were growing up on the farm, Mom made this soup with farm fresh sour cream, so it's not quite the same with commercial sour cream, but perfectly acceptable. Serves 4-6.
4 large potatoes*
1 large onion, chopped and sauteed lightly
1/2 cup sour cream
1 Tbsp flour
1/2 Tbsp vinegar, add to taste
salt and pepper
water to cover
Dice potatoes and cook in salted water. When potatoes are tender, add sauteed onions. Mix sour cream with flour, vinegar, salt and pepper; add to soup. Stir, simmer for a few minutes. Taste and add seasoning or vinegar to taste. We like ours a little tangy.* If you've got leftover mashed potatoes, add them to a vegetable or chicken stock. Saute the onions, add to soup. Simmer until hot. Add the sour cream mix (sour cream, flour, vinegar, seasoning) and simmer 2-3 minutes more.
Serve with hot biscuits or crusty bread.