Combine the first 5 ingredients in a small bowl and then set aside. Preheat oven to 450 degrees F. Line a baking sheet with parchment paper. Cut each radicchio in half through its core. Cut each half radicchio, through its core, into 3 wedges. Fill a large bowl with cold water. Gently swirl and wash the radicchio wedges in the water. Gently shake off the excess water and set in a single layer on the baking sheet. Roast until just tender and slightly wilted, about 15 minutes.
Arrange three wedges of radicchio on each of 4 plates. Quarter the pear lengthwise. Remove the core from each quarter pear, and then thinly slice. Arrange the pear slices over the radicchio. Drizzle with the olive oil/balsamic mixture. Sprinkle with pine nuts, top with nuggets of the cheese and serve.
Note: To toast the pine nuts, place in a single layer in a small skillet and set over medium heat. Cook, shaking the pan from time to time, until lightly toasted, about 5 minutes.