Place all the ingredients for the dressing in a jar. Seal tightly and shake vigorously until thoroughly combined. Set aside.
In a big bowl, toss together sliced pears, arugula, endive frisée, radicchio, and blue cheese. Add the dressing and toss again. Divide the salad among 4 plates. Top with chopped toasted walnuts and serve.
Notes
Tip: If you need to prepare this salad in advance, drizzle sliced pears lightly with lemon juice to prevent them from going brown and combine the salad with the dressing just before serving.