Place all dressing ingredients, except oil, in a blender and slowly drizzle in oil to emulsify. Trim the tops of the romaine lettuce and cut each of the heads in half lengthwise. Brush a small amount of the dressing on the cut side of the lettuce. Place lettuce, cut-side down, on a grill and cook for 2 to 3 minutes. Remove from grill and place on a serving platter. Drizzle with more of the dressing and garnish with croutons.
Wine-pairing suggestion: Full-bodied viognier such as Christine Andrew Viognier.