Shred the oyster mushrooms and place them in a large bowl. Season the shredded mushrooms with the olive oil, vinegar and 1 tablespoon of Old Bay seasoning, mixing it with your hands to ensure all the mushrooms are coated in the seasonings. Cover and marinate for 30 minutes.

In a soup pot over medium-high heat, add the marinated mushrooms and cook, stirring occasionally, until the outer edges start to crisp and most of the liquid has cooked out of the mushrooms, 15 to 20 minutes. Remove the mushrooms from the pot and set aside.

In the same pot, melt the butter over medium-low heat. Once the butter is melted, add the flour and mix with s wooden spoon until a paste forms. Continue to stir until there are no clumps. Add the onion, bell pepper, celery and garlic and season with the remaining tablespoon of Old Bay. Sauté, stirring often, until the onion is translucent and the garlic is fragrant, 4 to 5 minutes.

Pour in the diced tomatoes with their juices, broth, potatoes, thyme and bay leaves. Give the soup a mix to thoroughly combine and increase the heat to high. Once the soup reaches a boil, reduce the heat to low, cover and simmer until the potatoes are tender, 12 to 15 minutes. Add the sauteed mushrooms and soy milk and simmer, stirring often, another 5 minutes.

Serve immediately with fresh parsley, green onion and oyster crackers. Enjoy!