Saffron-Vanilla Seafood Stew

Make the stew: Trim the fennel stems and leaves and reserve. Cut the white bulb into 3/4-inch wedges. Cut the leek into 1/2-inch-thick rounds and separate the white and green ends. Rinse the clams and cut the fish fillets into 2-inch pieces. Set aside. Heat 1 tablespoon olive oil in a medium stockpot over medium heat, add the fennel trimmings, green parts of the leek, 1/2 teaspoon garlic, bay leaf, and orange peel and cook until vegetables are soft -- about 10 minutes. Season with 1/2 teaspoon salt and the pepper. Add the wine and cook for 1 minute. Add the vanilla bean pod and seeds, and 3 1/2 cups water. Bring to a simmer, reduce heat to medium-low and simmer, covered, for 25 minutes. Add the clams, and simmer, covered, until clams open -- about 7 minutes. Remove clams. Strain the broth; return it to the pot over medium heat. Add the saffron, remaining leek, and fennel wedges and simmer until tender -- about 15 minutes. Add the fish and cook until opaque -- about 5 minutes. Remove the fish. Keep covered. Add the tomatoes to the broth.

Serve the stew: Whisk the mayonnaise, 1 teaspoon cold water, and the remaining garlic, salt, and olive oil together. Slowly whisk 1/2 cup of broth into the mayonnaise mixture and stir into the broth. Add the fish and clams. Serve immediately.