6 whole large eggs boiled and chilled
12 whole romaine lettuce leaves for serving
2 to 3 tablespoons mayonnaise to taste, 2 for suggested but 3 for creamier filling
2 teaspoons smooth Dijon mustard for yolk filling
1/4 teaspoon Worcestershire sauce optional, for yolk filling
1/2 teaspoon lemon juice for yolk filling
2 tablespoons fresh flat-leaf parsley chopped, divided, half for filling and half for garnish
to taste salt for seasoning yolk filling
to taste freshly ground black pepper for seasoning yolk filling
1 tablespoon olive oil for preparing crumb topping
1 whole anchovy fillet minced, for crumb topping
1 clove garlic minced, for crumb topping
1/4 teaspoon lemon zest for crumb topping
1/4 cup panko bread crumbs for crumb topping
2 tablespoons Parmesan cheese freshly grated, for crumb topping, or more to taste