Bourride (Fish Stew with Aïoli)

Ingredients

• 2 tsp. fresh lemon juice
• 1 clove garlic, minced
• 1 egg yolk, at room temperature
• Kosher salt, to taste
• 1 cup olive oil
• 1⁄4 cup olive oil
• 1 tsp. fennel seeds
• 1⁄4 tsp. cayenne
• 2 cloves garlic, crushed
• 2 leeks, white parts only, roughly chopped
• 2 onions, roughly chopped
• 2 plum tomatoes, quartered
• 1 bay leaf
• 1 1⁄2 cups dry white wine
• 4 cups seafood stock
• 2 lb. skinless firm white fish, such as halibut or monk fish, pin bones removed
• 10 oz. medium shrimp, peeled and deveined, tails removed
• 1⁄2 tsp. saffron threads
• Kosher salt
• freshly ground black pepper
• 2 tbsp. minced parsley
• Toasted baguette, for serving