Heat a large, heavy-bottomed pot over medium heat. Pour in 1 tablespoon of olive oil. Add half of the sliced mushrooms and sauté until golden brown and tender, about 5 minutes. Season with salt and pepper. Transfer the cooked mushrooms to a bowl. Repeat this process with another tablespoon of olive oil and the remaining mushrooms. Once you have all the mushrooms cooked, set aside.

Add the remaining 2 tablespoons of olive oil to the pot. Add the onion, carrot, and celery and stir. Sauté this mixture, stirring often, until onions are soft and translucent, about 7-8 minutes.

To the pot, add the garlic, dried thyme, paprika, onion powder, garlic powder, and bay leaves and stir. Season with salt and pepper. Once the garlic is fragrant, after about 1 minute, add the pearled barley and lentils. Stir.

Add the vegetable stock and stir. Cover the pot and bring it up to a boil. Once boiling, lower the heat to a simmer and remove the lid. Simmer until barley and lentils are tender, about 30 minutes, popping in to stir here and there. Extract and discard the bay leaves.

Place the miso in a small bowl and ladle some of the hot broth from the soup on top. Use a spoon to break up and dissolve the miso. Then, add the mixture back into the pot. Add the mushrooms back into the pot as well. Then, add the non-dairy cream, sherry vinegar, Worcestershire, and dill. Stir to combine and bring up to a boil again. Give the soup a taste and adjust seasoning if necessary (more vinegar, salt, Worcestershire etc).

Serve the mushroom barley soup hot and enjoy!