Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   4      heads         radicchio di treviso
   4      tablespoons   virgin olive oil
   1      medium        red onion
     1/2  cup           grated parmigiano-reggiano -- plus 1/2 cup
     1/2  cup           finely-chopped Italian parsley
                        salt -- to taste
                        freshly-ground black pepper -- to taste
   1      tablespoon    balsamic vinegar
   1      recipe        basic fresh egg pasta -- see * note
                        (rolled to thinnest setting on machine)
   1      cup           whipping cream
   2                    egg yolks
     1/4  teaspoon      freshly-grated nutmeg
   8      tablespoons   butter

Preparation:

Chop radicchio into 1/4-inch pieces, rinse and spin dry. In a 12-inch to 14-inch sauté pan, heat olive oil until smoking over medium-high heat. Add onion and cook until softened and light brown, about 6 to 7 minutes. Add radicchio and toss until very soft, about 6 to 7 more minutes. Remove from pan and allow to cool. Place in mixing bowl and add one half cup Parmesan, parsley, salt and pepper and balsamic vinegar and stir well. Cut pasta into 4-inch squares. Place 1 tablespoon into center of each pasta square. Fold to form triangle and then fold ends together to form tortelloni. Continue until all pasta filling is finished. Bring six quarts water to boil and add 2 tablespoons salt. Place tortelloni in boiling water and lower heat to high-simmer. Meanwhile, bring cream to boil in 1-quart saucepan. Remove from heat, add remaining 1/2 cup Parmesan, yolks and nutmeg and stir through. Drain tortelloni and place into 12-inch to 14-inch sauté pan with butter and reserved radicchio and simmer over low heat. Place 3 tortelloni on each plate, spoon 2 tablespoons fonduta over the pasta and serve. Source: MOLTO MARIO with Mario Batali From the TV FOOD NETWORK - (Show # MB-5730)