Seafood Stew with Fennel and Thyme

In Normandy, this richly flavored stew would be served with a composed salad of watercress, shallots, and roasted beets.

1. Combine mussels, 1 1/4 cups onions, wine, and 8 parsley sprigs in large pot; bring to boil. Cover and cook until mussels open, shaking pot often, about 5 minutes. Using slotted spoon, transfer mussels to large bowl to cool (discard any mussels that do not open).
2. Strain cooking liquid into large measuring cup; discard vegetables in strainer. Add enough water to cooking liquid to measure 2 cups total. Remove mussels from shells if desired.
3. Melt butter in same large pot over medium heat. Add remaining 1 1/4 cups onions, leeks, and fennel and sauté until leeks are soft, stirring frequently, about 7 minutes. Add reserved mussel cooking liquid, 4 parsley sprigs, clam juice, thyme sprigs, and bay leaves. Simmer uncovered until vegetables are tender and liquid has reduced by 1/3, about 25 minutes.
4. Add halibut and scallops to broth and simmer until just opaque in center, about 4 minutes. Using slotted spoon, transfer halibut and scallops to bowl. Discard parsley sprigs, thyme sprigs, and bay leaves.
5. Whisk crème fraîche and egg yolks in medium bowl to blend. Whisk in 1/2 cup hot cooking liquid from pot. Gradually stir yolk mixture into stew. Cook over medium heat until liquid thickens slightly, stirring constantly, about 5 minutes (do not allow mixture to boil). Return halibut, scallops, and mussels to pan. Cook until halibut is heated through, stirring often, about 5 minutes. Stir in 1/2 cup chopped parsley.
6. Season with salt and pepper. Serve in warmed shallow bowls.

• Crème fraîche is sold at some supermarkets. If unavailable, heat 1 cup whipping cream to lukewarm (85°F). Remove from heat and mix in 2 tablespoons buttermilk. Cover and let stand in warm, draft-free area until slightly thickened, 24 to 48 hours, depending on temperature of room. Refrigerate until ready to use.
• What to drink: Muscadet, Chablis, or unoaked Chardonnay.