½ cup Olive Oil
4 Halibut fillets, each about 4 oz., skin removed
Extra-fine French grey sea salt, to taste
½ cup shallots
10 garlic cloves, thinly sliced
1 cup torn oyster mushrooms
1 cup thinly sliced fennel
1 cup diced zucchini
2 cups diced tomatoes
1 tsp. fennel seed
1 cup water
1 Tbs. bay seafood seasoning
½ lb. Manila clams
½ lb. mussels
½ lb. large shrimp, peeled and deveined, tails intact
2 Tbs. chiffonade of fresh flat-leaf parsley (very thinly sliced)
4 sprigs fennel fronds

In an 11- inch square griddle pan over medium heat, warm 2 Tbs. of the olive oil. Season the halibut fillets with French grey sea salt. Place the fish, skinned side up, in the pan and sear until golden, 3 to 4 minutes. Transfer to a platter.
Return the griddle to medium heat and warm 2 Tbs. olive oil. Add the onion, garlic, mushrooms, fennel, and zucchini and cook, stirring occasionally, until the vegetables are tender, 8-10 minutes; do not allow them to brown. Add the tomatoes and fennel seed and cook, stirring frequently, 1 to 2 minutes. Add the wine and stir to scrap up the browned bits from the pan bottom. Add the water and bay seafood seasoning and bring the mixture to a simmer.

Add the clams to the pan and simmer briskly until they start to open, 10 to 12 minutes, then move them to the edges. Place the Halibut, seared side up, in the center of the pan, and arrange the mussels and shrimp around the edges. Continue to cook, occasionally basting the fish with the broth, until the mussels open, the shrimp turn pink and opaque, and the halibut is cooked through, 4 to 6 minutes. Discard any clams and mussels that did not open. Drizzle the olive oil over the Halibut, sprinkle with the parsley and fennel fronds, and serve immediately.