Cut the meat into even pieces about 3 cm in size and trim off the fattest parts.
Peel and thinly slice the onion. Sauté it in a skillet with a pat of butter until it becomes translucent, then transfer it to a casserole dish—ideally a cast-iron one.
Brown the pieces of meat in small batches in the same skillet. Add a little butter between each batch if necessary, then transfer the meat to the casserole dish as you go.
Once all the meat is in the casserole dish, deglaze the skillet with a little water or red wine. Bring to a boil, scraping up the pan juices to extract as much flavor as possible. Season with salt and pepper, then pour the resulting liquid into the casserole dish.
Add the carrots, which have been sliced into rounds, along with the bouquet garni. Pour in enough red wine to cover the ingredients.
Let it cook over low heat for several hours so that the meat becomes tender and the flavors develop fully.
The next day, return the mixture to the heat and continue cooking for at least 2 hours. Add a little red wine or water as needed to keep the sauce thick and rich.
