preheat the ovens and stovetop.
In a large sauté pan, warm some oil over high heat. Add the shanks. Season well and caramelise for 2-3 minutes until coloured on all sides turning carefully with tongs. Transfer the lamb shanks to the casserole dish.
In the same pan, add the mushroom, season well with salt and pepper and sauté for 2 minutes with butter.
add the the onions, carrots, garlic, herbs, beans, tomato puree and mustard to the casserole dish. Season with salt, pepper. Stir to combine all the flavours together.
In the pan, add the mushroom, season well with salt and pepper and sauté for 2 minutes with butter. Add the passata and stock. Bring to simmer for 1 minute or so. Cover with the lid and transfer in the simmering oven. slow cook for 3 hours minimum up to 7-8 hours or until the meat is tender. Check the seasoning and serve with buttery mash potato.
