slice onions, and saute in oil till caramel color. add sliced carrots, pearl barley, and mushrooms. keep stirring (for about 5-7 minutes ) so it will not stick. add 3 litres of water. bring to boil. simmer for an hr. and a half (stir every 15 minutes) . add small amount of salt to taste.
I do not add additional seasoning, but of course you can if you like. also with the flour. I find if you simmer for an hr. and a half , and you let it sit for a bit it will become thick because of the pearl barley. the carrots just add extra color etc.
cooked carrots will add sweetness. you can also add a tbs concomme for some seasoning. make sure the soup has plenty liquid because all the veggies will sop up liquid as it sits. the soup can become a stesw.