To make marmalade:
Place chopped red onions, Lambrusco, orange juice and sugar in a saucepan and place over medium high heat. Bring to a boil, lower heat to medium and reduce until thick like marmalade, about 30 minutes. Remove from heat and allow to cool.
To make filling:
In a 12- to 14-inch saute pan, melt butter over medium heat until just starting to foam. Slice raw chicken very thinly across the grain and place in pan with butter. Cook over medium heat, stirring constantly, until very lightly browned. Add wine, cover and cook for 5 minutes. Remove cover and cook until liquid is gone, 2 to 3 more minutes. Remove from heat and allow to cool. Cut prosciutto and mortadella into 1/4-inch dice and place in food processor. Add cooled contents of saute pan and pulse until just ground, like meat, not like a mousse. Pour into a large mixing bowl and add cheese, nutmeg, milk and egg, folding carefully. Check for seasoning with salt only and refrigerate.
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.
To assemble tortellini:
Lay out 1 sheet of pasta and cut into 2-inch rounds using a water glass or cookie cutter. Cover cut rounds with a damp kitchen towel so that they do not dry out. Working 5 at a time, place 1/2 teaspoon filling in center of each round. Fold each round in half to form a half moon and pinch the edges tightly together to seal. Take the two opposing corners and bring the tails of the half moon together, twisting one half turn so that the sealed half round edge curves around the outside of the filled soul of the tortellini. Repeat with each round until all pasta is used up. Leave formed pasta shapes uncovered to dry.
To serve, heat the chicken stock to boil in a large pasta pot and add onion marmalade. Check broth for seasoning with salt. Drop 48 tortellini into broth and return to boil. Lower heat until just under boil and cook tortellini until tender and yet still possessing a discernible resistance to the bite, about 4 to 6 minutes. Spoon 12 tortellini into each of 4 warm soup bowls and divide the broth among them. Sprinkle with grated Parmigiano-Reggiano and serve immediately.