Step 1Heat the oven to 350 degrees. In a large bowl, toss the cubed focaccia with the olive oil until evenly coated, then toss with the salt. Spread the bread on a large, rimmed baking sheet and toast until golden and crunchy, 15 to 20 minutes.
Step 1Using a mortar and pestle, or in a food processor, grind the garlic and anchovy into a paste.
Step 2In a medium bowl, combine the garlic-anchovy paste with the lemon zest, red wine vinegar, 1 to 2 dashes of Worcestershire sauce and egg. Whisk to combine, then whisk in the lemon juice.
Step 3While whisking, slowly drizzle in the olive oil to thicken and emulsify the dressing. Season and adjust the flavoring as desired. This makes about 1 cup dressing, more than is needed for the remainder of the recipe. The dressing will keep, covered and refrigerated, for 2 to 3 days.
Step 1In a large bowl, toss the romaine leaves with dressing just to coat. Plate the salad on a serving platter or on individual plates. Sprinkle the Parmigiano evenly over the salad, and top with the croutons. Serve immediately.