In a medium-sized jar, combine minced shallots, sherry vinegar, whole-grain mustard, honey, kosher salt, and freshly cracked black pepper. Secure the lid and shake vigorously until well combined. Gradually whisk in extra-virgin olive oil until smooth and emulsified. Set aside to meld flavors.

Slice half of the fresh Brussels sprouts in half lengthwise for sautéing. Shred the other half thinly, creating delicate ribbons.

Toast pecan halves over medium heat in a dry skillet for 3-4 minutes until fragrant. Transfer to a plate to cool.

Sauté the halved Brussels sprouts in olive oil for 3-4 minutes until golden brown, then cook an additional 3-5 minutes until tender yet crisp. Set aside to cool.

In a large salad bowl, combine sautéed Brussels sprouts, shredded raw Brussels, diced red pear, toasted pecans, and chopped celery. Sprinkle with grated Pecorino Romano if using. Pour the dressing over and toss gently until well-coated.