Cioppino (San Francisco Seafood Stew)

Steps

1. Put the clams in a bowl of cold water with the coarse salt and let them sit for 20 minutes to spit out their sand. Meanwhile, scrub the mussels under cold water, pull off their beards, and discard any mussel that is cracked or stays open when tapped. Rinse the clams, drain, and keep everything refrigerated.
2. Thinly slice the onion and fennel (save a few green fennel fronds for the end). Mince 6 garlic cloves and keep the seventh whole for the toast. Cut the cod into 1 1/2 inch (4 cm) chunks, pat dry with paper towels, and salt lightly.
3. Heat 3 tablespoons of the olive oil in a large Dutch oven over medium heat. Add the onion, fennel and a pinch of the fine salt, and cook for 10 minutes, stirring, until soft and translucent, barely golden at the edges.
4. Add the minced garlic and red pepper flakes and stir for 1 minute until fragrant. Add the tomato paste and press it against the bottom of the pot for 2 minutes: it should darken from bright red to brick red.
5. Pour in the wine, scrape up the browned bits with a wooden spoon, and let it bubble for 3 to 4 minutes, until reduced by half and the smell of alcohol is gone.
6. Add the crushed tomatoes, fish stock, bay leaves, oregano, the rest of the fine salt, and the pepper. Bring to a boil, then lower to a steady simmer and cook for 25 minutes, partly covered: the broth should thicken slightly and coat the back of a spoon. Taste and adjust; it should be well seasoned, since the fish adds no salt.
7. While the broth simmers, heat the oven broiler to 425°F (220°C). Brush the sourdough slices with 2 tablespoons of olive oil and toast for 2 to 3 minutes per side, until golden with crisp edges. Rub them right away with the halved garlic clove.
8. Remove the bay leaves. Turn up the heat to a lively simmer, add the clams, cover, and cook for 4 minutes: they will start to open.
9. Slip the cod into the broth without stirring, lay the mussels on top, cover, and cook for 3 minutes. Add the shrimp, nudge them into the liquid, cover again for 2 to 3 minutes, until the shrimp are pink and curled into a C, all the shellfish have opened, and the fish is just opaque in the center, 130 to 140°F (55 to 60°C). Discard any shellfish that stay closed.
10. Chop the parsley with the fennel fronds. Ladle the cioppino into shallow bowls, giving everyone some of each seafood and plenty of broth. Scatter the herbs on top and serve with lemon wedges and the garlic sourdough toast.