1. Preheat the oven to 160 °C. Dust the shanks with seasoned flour. heat the oil and butter and brown the shanks in a casserole on all sides until golden brown.
2. Remove the shanks from the casserole and drain off any excess fat. Put the garlic, thyme and rosemary in an oven-safe casserole dish and put the shanks on top, then pour over the chicken stock. Cover the casserole with a lid or foil and cook in the oven for 2½ to 3 hours.