Place mushroom rounds in a medium size bowl filled with hot water. Soak 5 minutes then drain and pat dry.
To a large skillet over medium high heat, add vegan butter. When butter is melted, add mushrooms and cook 3-4 minutes, until browned. Flip and cook the other side another 3-4 minutes, until browned. Remove from heat and cover to keep warm.
To a large pot over medium high heat, add olive oil. Add celery and onion and cook 3-5 minutes, stirring frequently, until softened. Add garlic and cook 1 minute.
Add garbanzo beans, Roma tomatoes, vegetable broth, and Old Bay seasoning. Reduce heat to low and simmer 15 minutes. Stir in lemon juice and 1 tablespoon chopped parsley. Adjust seasoning to taste with salt and ground black pepper.
To serve, ladle the cioppino into shallow bowls and top with the mushroom "scallops". Sprinkle with remaining parsley.