Brush the romaine lettuce halves with the olive oil. Place them on the preheated grill and cook for 3-5 minutes, until lightly charred and slightly wilted.
In a small bowl, mix together the balsamic vinegar, dijon mustard, salt, and pepper. Whisk together until combined.
Remove the grilled lettuce from the grill and place on a serving platter. Drizzle with the balsamic vinaigrette and sprinkle with the Parmesan cheese.
Serve immediately.
Interesting Facts
Romaine lettuce is a great source of vitamins A and K.
Balsamic vinegar is made from grapes and has a sweet and tart flavor.
Grilling the lettuce adds a smoky flavor to the salad.
Parmesan cheese is a hard Italian cheese with a sharp flavor.