Green Bean Soup with Tarragon

I found the recipe for one of my favorite soups on a Hungarian website (http://www.szantal.hu/index.php?link=news%2Fnews.php&parentid=249&topic=6), and tweaked it a little, by adding some carrots to the recipe and skipping the unhealthy roux (called rántás in Hungarian) as a thickening agent...

Here's my version:

Ingredients:
1.5-2 lb fresh green beans
5-6 tomatoes, or 1 (14 oz) can chopped tomatoes when they are not  in season, or a combination of the two
4-5 carrots
1 shallot
4-5 cloves of garlic
2 (32 oz) chicken stock (or 64 oz water and 3 cubes chicken  bouillon)
2 cups kefir
1 bunch fresh tarragon, or 1 tbsp dried tarragon
a pinch of sugar
salt and black pepper to taste,
1 tbsp vegetable oil, or olive oil, or sunflower oil
1 tbsp flour

Preparation:
Clean and cut the beans into 1-1.5 inch pieces, cut the carrots into thin rounds, finely chop the onion. In a large soup pan heat the oil on medium, add the onions, and cook for 1-2 minutes. Add the carrots and green beans with 1/2 cup water, and cook for 10 minutes. In the meantime, bring the chicken broth (or water) to boil, and add it to the pan (and the chicken bouillon, if using). Simmer the vegetables for about 15-20 minutes, until beans are almost done. Add the tomatoes, and cook another 5 minutes. Meanwhile, combine 1 tbsp flour with the kefir, crush the garlic and add it tot he mixture. Remove the pan from the heat. Add the flour-kefir mixture, bring to boil,  cook for 1 minute, then adjust seasoning for salt and pepper, add the sugar and tarragon, and you're done. This is a very light, very flavorful, great summer soup. Enjoy!