In a small bowl, whisk together the olive oil, lemon juice, honey, Dijon mustard, chopped tarragon, and salt until smooth and lightly emulsified.
In a separate bowl, combine the sliced celery and halved grapes. Add half of the dressing and toss gently to coat.
Arrange the torn burrata on a serving plate, keeping it in soft, creamy mounds.
Add the chopped apple evenly over the burrata.
Spoon the celery and grape mixture over the top.
Drizzle the remaining dressing over the salad.
Finish with toasted walnuts and an optional sprinkle of extra tarragon.
Serve immediately.