In a large bowl combine garlic, ginger, Chinese five spice, soy sauce, black bean sauce and rice wine vinegar. Add lamb and mix until well coated. Place in refrigerator and leave for 2 to 3 hours to marinate.

Heat peanut and sesame oil in a large frying pan and brown meat in batches to avoid overcrowding the pan.

Set meat aside in a bowl. Lightly fry spring onions then return meat to the pan. Dissolve cornflour in a little beef stock then add stock and cornflour mix to pan. Bring to the boil then reduce heat and then simmer for 15 minutes until meat is cooked through and sauce slightly thickened.

Serve Mongolian lamb with steamed basmati rice.