Celery Root And Pear Remoulade With Walnuts

Name: Celery Root And Pear Remoulade With Walnuts
Ingredients: 2 large egg yolks, at room temperature; 1 tablespoon water; 1 1/2 teaspoons Dijon mustard; Salt and freshly ground white pepper; 3/4 cup vegetable oil; 6 tablespoons fresh lemon juice; 1 large hard-cooked egg, finely chopped; 1 tablespoon finely chopped cornichons or sour gherkins; 1 tablespoon finely chopped capers; 1 tablespoon finely chopped parsley; 1 1/2 teaspoons chopped tarragon; 1 small garlic clove, minced; 1/2 cup walnuts; 1 1/2 pounds celery root, peeled; 3 firm Bosc pears, peeled; 1/2 cup celery leaves from the heart