Cut the rabbit in 8 to 10 pieces. Season with salt and ground pepper.
Heat the oil and butter in a heavy cooking pot or a cocotte over a medium heat and sauté on all sides for 3-4 minutes. When the rabbit is nicely brown, transfer it to a tray.
Add the onions, shallots and garlic to the cocotte and cook until translucent.
Return the rabbit to the cocotte, add the bouquet garni, the Belgian beer, stock and add water to cover the meat.
Spread the Dijon mustard on the bread and place it on the meat.
Simmer the rabbit for 45 to 60 minutes until soft and tender. Gently stir the meat regularly and make sure there is enough liquid at all times.