Place the oil or fat in a large enough pan and warm up
Add the bones and meat and lightly brown the pieces by frying on low to medium heat and turning the pieces now and then
Cut the onion in large pieces and add them to the pan
Add all the water, the bayleaves, salt and pepper and bring close to a boil
When foam and scum starts to appear, remove these with a small sieve. Continue to do this, until the soup comes to a very slow simmer
Keep the soup at a very soft simmer for 4-5 hours
Taste the soup and adjust salt or pepper level . If desired, add a broth tablet or a little soy sauce
Thereafter, remove the bones and reserve the meat. You can use it for ragout, or add it later back to the broth
Let cool down and refrigerate over night
The next day, remove the hard surface fat layer and discard (or use for frying later)
A clean broth results. If you want the broth to be super clean, filter while warm over a cloth.