Bouillabaisse with Seared Halibut

• 1/4 cup extra-virgin olive oil
• 1 small fennel bulb, bulb sliced and fronds reserved
• 1 small yellow onion, diced
• 1 tablespoon minced garlic
• 1 teaspoon saffron threads
• 1 3/4 cups dry white wine
• 2 tablespoons licorice liqueur, such as Pernod
• 1 3/4 cups chopped fire-roasted tomatoes, with liquid
• 1 3/4 cups fish stock
• 1 teaspoon dried thyme leaves
• 1 bay leaf
• 2/3 pound gold creamer potatoes
• 2/3 pound littleneck clams, in the shell
• 2/3 pound mussels, in the shell
• 1/3 pound U 21/25 shrimp, peeled and deveined with tail
• Four 6-ounce halibut fillets, boneless and skinless
• Kosher salt and freshly cracked black pepper
• 4 tablespoons chopped fresh parsley
• 3 scallions, chopped
• 1 lemon, cut into wedges
• Garlicky Rouille, for serving, recipe follows

Garlicky Rouille:

• 1/3 pound fingerling potatoes, cooked
• 1/4 cup jarred fire-roasted red peppers
• 3 cloves garlic
• 1 cup mayonnaise
• 1 teaspoon lemon juice
• 1/2 teaspoon sweet paprika
• Pinch cayenne, or as needed
• Kosher salt