I did some research on this for you and found that there are lots of opinions. According to my research, just about all ancient peoples had some sort of soup. Apparently it was a common thing for ancient peoples to put meats, vegetables, roots, etc. into water and cook it. In fact, soups and stews are mentioned in the Bible. You don't say if you need proof to back up your answer but if you do, then you would have to do some preliminary research and find an article to cite to prove what you have found. There probably is no definitive answer to this, so if you have to pick a country you could pick a country where you know remains of ancient men have been found - for example Germany (Neanderthal man found there) or Turkey (early man skeletons found there), assuming that wherever there were men, there was soup. They had the ingredients - they had meat, they had wild fruits/vegetables, they had water, they had fire.