Peel the carrots and onion, wash the celery, keep large pieces so you can easily fish them out later.
Stick the cloves into the onions and put everything in a large pot, season with pepper and salt, thyme, and bay leaf, and cover completely with water over medium heat.
Once it boils, lower the heat a bit so it simmers gently but surely, skim occasionally, and let it cook for another hour until the meat is tender.
Remove the carrot, celery, and onion so that you only have the tender pieces of meat left.
Carefully pour into a colander with a pot underneath, catch the broth, and bring it back to a boil.
Cut the mushrooms in half or into quarters, put everything in a saucepan, cover with a circle of baking paper or a lid, and let simmer for 5 minutes until they are nicely shrunk and glossy.
Mix everything for the meatballs together, roll into balls.
Peel the carrots and the strings from the celery, cut into diagonal pieces.
Add the meatballs, celery, and carrot to the broth, once it boils again, lower the heat and let it simmer for 5 minutes, and strain again, catching the broth.
Let the butter melt in a large pot and let it foam, add the flour all at once and let it cook a bit, then add a good splash of broth, about 500 ml.
Whisk well until you have a smooth thick paste and add splashes of broth until the desired thickness is reached.
Let it cook well for a moment and add the cream last, bring to a brief boil.
Now add the meat, meatballs, mushrooms, and vegetables, mix well and bring to a boil one last time.
Serve with potatoes, mashed potatoes, or rice.