Rehydrate the dried mushrooms in 2 cups of hot water for 30 minutes. Drain, reserving the liquid, and mince the mushrooms.

In a large pot, heat olive oil over medium-high heat. Add onion, fresh mushrooms, carrots, and celery and sauté for 5-7 minutes.

Sprinkle flour over the vegetables and stir to coat. Cook for another 2-3 minutes.

Add the reserved mushroom liquid and vegetable broth. Bring to a boil.

Reduce heat to low, cover, and simmer for 15 minutes.

Add barley and simmer for another 10 minutes, or until barley is softened. If using regular barley, it will take an extra 20 minutes.

Stir in parsley and dill.

In a separate bowl, whisk together sour cream with 1 ladle of hot soup. Add to the pot and stir to combine.

Season with salt and pepper to taste.