For an even richer flavor, toast the hazelnuts in a dry skillet over medium heat for 5-7 minutes before chopping. This brings out their nutty aroma. If you don't have fresh thyme on hand, you can substitute 1 teaspoon of dried thyme in the vinaigrette. Feel free to experiment with different types of pears, such as Anjou or Bosc, depending on your preference and availability. To keep the arugula crisp, wash and thoroughly dry it before adding it to the salad. The vinaigrette can be made ahead of time and stored in the refrigerator for up to 3 days. Just be sure to shake it well before using.