Fennel Mussels With Piquillo Rouille

Name: Fennel Mussels With Piquillo Rouille
Ingredients: 1/4 cup plus 2 tablespoons fish stock or bottled clam broth; Large pinch of saffron threads; One 1/4-inch-thick slice of peasant bread, crust removed; 1 large egg yolk; 1 jarred piquillo pepper, chopped; 2 garlic cloves, chopped; 2 teaspoons fresh lemon juice; 1/2 cup extra-virgin olive oil; Cayenne pepper; Salt; 2 tablespoons extra-virgin olive oil; 2 heads of fennel, cored and diced, plus 1/4 cup chopped fronds; 1 medium onion, diced; 4 garlic cloves, minced; 1/2 teaspoon crushed red pepper; 1/2 cup Pernod or absinthe; 1 1/4 cups fish stock or bottled clam broth; 4 pounds mussels, scrubbed and debearded; 1 tablespoon unsalted butter; 1/2 cup chopped parsley