Prepare the broth by combining all ingredients in a large pot and bring to a boil. Allow to simmer gently 30 minutes over low heat. Filter.
In a saucepan, brown the onion in the oil, 5 minutes over medium heat. Include the rice and stir for 2 minutes to flavor. Add the mushrooms and wine and deglaze. Do the same with the ham and mix.
Pour 250ml of broth in the risotto pot and shake gently, so that the rice does not burn on the bottom.
About 5 minutes later, add 250ml more of broth and stir.
Continue cooking the rice for about 15 minutes.
Remove from heat, add parsley, butter and Parmesan and stir 1 minute before serving.