Ingredients

1 can (14.5 ounces) whole peeled tomatoes in juice 

1 roasted red pepper (from a 12-ounce jar) 

2 tablespoons extra-virgin olive oil 

3 tablespoons unsalted butter 

8 ounces king-oyster mushrooms (3 to 6, depending on size), cut into 3/4-inch-thick "scallops" 

Kosher salt and freshly ground pepper 

1 small onion, chopped (1 cup) 

2 celery stalks, cut into 3/4-inch pieces (1 cup) 

3 cloves garlic, thinly sliced (1 packed tablespoon) 

2 teaspoons fresh thyme leaves 

1 1/2 teaspoons Old Bay seasoning 

1/2 cup dry vermouth 

1 can (15 ounces) seafood or fish broth, such as Bar Harbor; or 2 bottles (each 8 ounces) clam juice 

5 ounces beech mushrooms, removed from foot 

12 ounces skinless cod or halibut fillet, cut into 1 1/4-inch pieces 

12 ounces medium shrimp (about 25), peeled and deveined 

8 ounces jumbo lump crabmeat (optional) 

Crostini or biscuits, for serving

Preparation

Combine tomatoes and red pepper in a blender; purée until smooth. Heat a large straight-sided skillet or braiser pan over medium-high. Add 1 tablespoon oil and 2 tablespoons butter.

When butter melts and foam subsides, add king-oyster mushrooms in a single layer. Season generously with salt and pepper and cook, flipping once, until golden brown on both cut sides, 6 to 8 minutes. Transfer to a plate.

Heat remaining 1 tablespoon each oil and butter in skillet over medium. Add onion and celery; cook, stirring occasionally, until tender and golden in places, about 5 minutes. Add garlic, thyme, and 1 teaspoon Old Bay and cook until fragrant, about 1 minute. Add vermouth; cook until mostly evaporated, about 2 minutes.

Return king-oyster mushrooms to skillet with tomato mixture, broth, and beech mushrooms. Bring to a boil, then reduce heat to medium-low and simmer 5 minutes.

Meanwhile, season fish and shrimp with remaining 1/2 teaspoon Old Bay, salt, and pepper; nestle into skillet. Simmer, gently stirring a few times, until just cooked through, about 5 minutes. Nestle crabmeat into skillet and cook until warmed through, about 30 seconds. Serve with crostini or biscuits.