In a frypan, toast the walnut pieces over a medium-low heat for about 5 minutes. Remove from heat, allow to cool, then coarsely chop and set aside.
In a large bowl, whisk together the vinegar, honey, mustard, salt and pepper. In a thin stream, add the olive oil, whisking continuously until the dressing is thick and smooth.
Into the dressing, add the salad leaves, pears, pomegranate seeds and walnuts, and gently toss to coat. Garnish with cheese and serve immediately.
If making this salad ahead of time, prepare all ingredients and only toss through the dressing when ready to serve.