Toss the butternut squash with the olive oil in a small bowl. Arrange in a single layer on a baking sheet.
Roast the butternut squash for 25-30 minutes until fork tender and golden brown. Cool to room temperature.
Toss the arugula and watercress together and arrange on a large serving platter.
Top the greens with the pear, apple, celery, cranberries, pomegranate seeds and pecans.
Make the dressing by whisking together the clementine juice, apple cider vinegar and mustard. Slowly stream in the olive oil while continuing to whisk.
Season with salt and pepper, to taste.
Drizzle the dressing over the salad and toss to coat or serve on the side to dress as needed.
Notes
Watercress is added because the arugula is more bitter. All arugula can be used for this salad if you can’t find watercress.