Preheat the oven to 200°C/gas 6.
To make the broth, put the chicken carcasses in a roasting pan. Roast in the preheated oven for about 1 hour, stirring occasionally, until well browned. Transfer the bones to a stockpot.
Put the onion, carrot and celery in the roasting pan, and roast for 20-30 minutes, until browned. Add to the bones in the stockpot.
Cover the bones and vegetables with cold water. Add the tomato, bay leaf, peppercorns and cloves. Bring slowly to the boil, skimming off impurities that rise to the surface. Reduce the heat and simmer over medium heat for 1hour 30 minutes, continuing to skim from time to time.
Line a colander with wet muslin. Slowly pour the stock through the cloth, leaving the debris behind. Remove the bones from the debris. Push the vegetables through a fine sieve to extract all the juices. Add these to the stock.
While the broth is cooking, make the filling for the tortellini. Put the chicken and mortadella in a food processor. Add the egg, nutmeg, breadcrumbs, Parmesan and a little salt. Purée until smooth. Scrape into a bowl, cover and put in the fridge.
Now make the pasta. Sift the flour and salt into a food processor bowl. Switch on to medium speed and slowly pour in the whole egg and yolks. When the mix forms a dough, place onto a clean work surface and knead for 10-15 minutes until smooth.
Wrap the dough in cling film, and leave to rest in the fridge for at least 20 minutes.
Cut the dough in half and flatten slightly with a rolling pin. Work the dough through a pasta machine, starting at the thickest setting.
. Fold each sheet back on itself and repeat, thinning it each time on a finer setting until the pasta is paper-thin.
. Now cook the filling. Bring a pan of water to the boil. . With 2 teaspoons, mould the filling into ovals and drop into the boiling water. Cook for about 2 minutes then remove with a perforated spoon.
. Cut the pasta into 6cmsquares. Place the filling in the middle, moisten the edges of the squares then fold them in half to form triangles. Press the edges together to seal.
. Fold the two long corners around your finger, overlapping them and pressing to seal. Fold the top of the triangle away to make the tortellini shape. Mould into a round shape. Place the shapes on a clean cloth, spaced well apart.
. Bring the broth to the boil in a large saucepan and toss in the tortellini, a few at a time, Cook over high heat for 3-4 minutes. Transfer to soup plates using a perforated spoon.
. Pour over the broth and serve.