Brown the lamb rack in hot oil. Transfer to a hot oven set at 180C for 10-12 mins. Leave to rest on a cold tray for at least 15 mins.
To make the Scotch broth, cook the barley in the chicken stock over a low heat for 30 minutes. Add the vegetables and pour in the reserved lamb stock. Season to taste, then cover with a lid and cook gently for another 30 minutes or so until the vegetables and barley are completely tender.
Slice the rack into cutlets (2-3 each). Serve with the rissoles and Scotch broth. However you could leave the rissoles out if you’d prefer a simpler meal.