How to Make It
Preheat the oven to 350°. Spread the hazelnuts in a pie plate and toast for about 8 minutes, until lightly golden and fragrant. Let cool, then transfer to kitchen towel and rub them together to remove the skins. Coarsely chop the hazelnuts.
In a large bowl, whisk the cider vinegar with the mustard and salt. Gradually whisk in the hazelnut oil. Add the celery, Asian pear, dill and hazelnuts and toss to coat. Serve immediately.