1. Wash the chicken, place in a pot, add cold water to cover and bring to a boil. Reduce heat to a gentle boil and cook for 40 minutes. Let cool.
2. Wash the tongue carefully and place it in a large pot of cold water (use enough to cover). Add peppercorns, bay leaves and salt (I also put a couple of baby carrots, onion and some dill, but that's absolutely optional). Bring to a boil and simmer for about 2,5 hours. Remove from water and when it's cool enough to handle, peel the skin (if you remove the tongue from the pot and put it immediately into cold water, this will make it very easy to peel).
3. Cut the tongue into 1/4 inch slices, and then into thin strips.
4. Cut the ham in the same way as you did the tongue.
5. Cut the mushrooms into strips.
6. Tear the chicken into strips.
7. In a large bowl, combine beef tongue, chicken, ham and mushrooms. Dress with balsamic vinaigrette. Refrigerate until serving.