Caesar Salad with Crouton Collars

Name: Caesar Salad with Crouton Collars
Ingredients: 1 (4-inch thick) sourdough or French baguette, cut into 2-inch thick slices; 1/2 cup olive oil; 1 egg yolk, coddled; 1/4 teaspoon salt; 1 teaspoon coarsely ground black pepper; 4 garlic cloves, minced; 2 anchovies (or 1 teaspoon anchovy paste); 2 teaspoons Dijon mustard (the real stuff, not the dried stuff); 1 1/2 tablespoons freshly squeezed lemon juice; 1 teaspoon Worcestershire sauce; 1/4 cup safflower oil, or olive oil; 1 1/2 teaspoons red wine vinegar; 2 large heads romaine lettuce, outer leaves discarded, remaining inner leaves washed and thoroughly dried; 4 crouton collars; 1/2 cup freshly grated imported Italian Parmigiano-Reggiano