Ingredients

• 1 large russet potato, scrubbed and cut into wedges

• 4 tablespoons extra-virgin olive oil, divided

• ½ teaspoon ground pepper, divided

• ¼ teaspoon salt

• ¼ teaspoon cayenne pepper

• 1 large egg yolk, pasteurized, if desired

• 1 teaspoon minced fresh parsley plus 1 tablespoon, divided

• 1 teaspoon lemon juice

• ½ teaspoon minced shallot plus 1 tablespoon, divided

• ½ teaspoon whole-grain mustard

• ½ cup chopped leek

• 2 pounds mussels, scrubbed and debearded (see Tip)

• ¾ cup dry white wine, such as chardonnay or pinot grigio

• Sliced scallions & crushed red pepper for serving