Place the chorizo in a food processor and process until the pieces are small and well ground. In a Dutch oven or large heavy pot heat a 2-count of olive oil (about 2 tablespoons) over medium heat; cook the ground chorizo until brown and the fat is rendered. Meanwhile, drain the tomatoes, reserving the juice. Hand-crush the tomatoes. Add the onion, garlic, celery, and hand-crushed tomatoes to the food processor and process until a smooth, slightly pulpy consistency is reached.

Once the ground chorizo is cooked, add the vegetable puree, the thyme, and bay leaf to the pot and saute for 5 to 7 minutes more. When the liquid has reduced a little, dust with the flour and stir well to form the base of a roux. Add the reserved tomato juice, the red wine, and chicken broth. Season lightly with salt and pepper, then cover (leaving lid slightly askew) and simmer for 1 hour.

Turn up the heat and add the crabs and clams to the broth. Cover and steam about 10 minutes, until clams open. Discard any that don't open. Reduce heat; add shrimp, halibut, and lemon; gently mix to coat everything. Simmer gently until shrimp turn pink and fish is cooked through; remove from heat. Serve Cioppino with Sourdough Garlic Toasts and top with a spoonful of reserved garlic butter and some fresh parsley.

Sourdough Garlic Toasts: Preheat oven to 350 degrees Fahrenheit. In a bowl combine 1/2 stick room-temperature unsalted butter; 2 garlic cloves, peeled and minced; and 2 tablespoons chopped fresh Italian flat-leaf parsley; stir to mix. Season with kosher salt and freshly ground black pepper. Cut 1 loaf of sourdough bread into slices, leaving them connected at the base so the bread is still in a loaf. Smear the insides of the bread slices with some of the garlic butter (set aside remaining butter for Cioppino). Place loaf on a baking sheet. Toast the whole loaf about 10 minutes, until crispy and fragrant. Top servings of the Cioppino with leftover garlic butter.