Make a mound of the flour in the center of a large wooden cutting board. Make a well in the middle of the flour and add the eggs, oil and any other flavoring you choose. Using a fork, beat together the eggs, oil and flavorings and begin to incorporate the flour starting with the inner rim of the well. As you expand the well, keep pushing the flour up to retain the well shape. Do not worry that this initial phase looks messy. The dough will come together when 1/2 of the flour is incorporated.
Start kneading the dough with both hands, using the palms of your hands primarily. Once you
have a cohesive mass, remove the dough from the board and scrape up any left over crusty bits.
Lightly flour the board and continue kneading for 3 more minutes. The dough should be elastic and a little sticky. Continue to knead for another 3 minutes, remembering to dust your board when necessary. Wrap the dough in plastic and allow to rest for 30 minutes at room temperature. Note: do not skip the kneading or resting portion of this recipe, they are essential for a light pasta. Yield: 1 pound
To Make Salsa Balsamella:
Melt butter in a 2-quart saucepan until frothing. Remove from heat and stir in flour with a whisk. Cook over low heat for 4 to 5 minutes, stirring constantly. Add 1/2 hot milk an whisk until smooth. Add remaining milk and whisk until smooth. Bring to boil, add nutmeg, lower heat and simmer 10 minutes.
Can be used hot or cold.
To Make Tortelloni Al Forno:
Preheat oven to 425 F. Bring 6 quarts of water to boil and add 2 tablespoons salt.
Heat oil in a 12 to 14-inch saute pan until smoking and add onions. Cook onions until softened but not brown, about 1 to 2 minutes. Add radicchio and cook until softened and lightly gray in color, about 5 to 6 minutes. Remove from heat and allow to cool.
Meanwhile, drop tortellini into boiling water and cook until tender. Gently drain and place in a large mixing bowl. Add cooled radicchio mixture, balsamella and half the grated cheese. Gently stir to mix well. Divide among 4 buttered gratin dishes, sprinkle with the remaining cheese and bake until bubbly and crusty on top, about 20 minutes. Serve immediately.