Heat oil in large soup pot. When hot, saute onion for 5 minutes, take
care not to let it brown. Add potatoes and fry for, covered for 3
minutes. Add oregano, basil, parsley, salt & pepper. Cook covered for 2
minutes. Add tomatoes and cook for another 5 minutes. Add the stock,
bring to a boil, reduce heat & simmer for 20 minutes, or until the
potatoes are tender. Check seasonings. Let cool, blend till smooth.
Reheat before serving, but take care not to let it boil.