Clean the chicken and wash it thoroughly. Place it in the bottom of a large pot.Pour cold water over it so that it covers the meat. Place the pot on the stove and bring the water to a boil. When it boils, foam will form on the surface. Remove this with a strainer. Repeat the process until no more foam forms. Then lower the heat so that the soup simmers gently. Now it's time for the salt. You can add the whole black peppercorns straight away, but if you don't want to pick them out one by one at the end, I recommend putting them in a tea egg. Fill the bottom of the tea egg with whole black peppercorns and simply hang it in the soup. This way, you can remove it all at once at the end.
Wash an onion with the skin on. Cut it in half. Fry the cut side down in a dry pan, then add it to the soup. You can do the same with a head of garlic.
Simmer the soup for 2-3 hours. This depends on the quality of the meat. After 2 hours, check how tender it is and cook for longer if necessary.
Add the vegetables 1 hour after boiling. Clean the soup vegetables and leave them in large pieces, then add them when the meat is almost tender. The key is to cook them at the same time so that the vegetables do not overcook and remain bite-sized.
When everything is tender, remove the meat and vegetables with a slotted spoon.
It is worth letting the finished soup rest for at least 30 minutes, then straining it. If you want a very clear, almost fat-free soup, you can also use a cloth diaper. I simply pour the soup through a fine-mesh strainer into the bowls. The strainer is needed to filter out any bone fragments that may remain in the soup.