How to Make It
Preheat the oven to 350°. In a large bowl, whisk the red wine vinegar with the olive oil and season with salt and pepper. Add the radicchio and arugula and toss well. Mound the salad on oven-proof plates and top with the shaved cheese. Arrange the plates on trays and warm the salads in the oven for about 1 minute, until the cheese is just melted. Sprinkle the toasted hazelnuts on top. Drizzle a little saba over the salads and serve right away.
Saba, the Italian condiment made from reduced grape must, is available at specialty food stores and from igourmet.com.