Heat a pot over the stove and add the ghee. Chop the onion and sauté it until fragrant. Add the beef shank and sear it on all sides. Pour in just enough hot water to cover the meat, then add the thyme and rosemary. Cover and cook until the meat is about three-quarters done.

Mix all the marinade ingredients together well. Remove the beef from the broth and let it cool slightly, then coat it thoroughly with the marinade.

Arrange the beef in a baking dish greased with ghee. Roast in the oven until browned and fully cooked through.