Preheat the oven to 160°C.
Place the garlic, ginger, soy sauce, Chinese 5 spice powder, honey, rice wine and chilli flakes in a medium mixing bowl. Stir until mixed.
Add the whole lamb steaks and mix until well coated.
Place a large piece of foil in a roasting tin and place the lamb and marinade in the centre. Wrap the foil to make a parcel.
Place in the preheated oven for 1 ½-2 hours, until the lamb shreds easily. Check the lamb towards the end of cooking and test to see if it is ready to shred with two forks.
Remove the lamb from the oven. Preheat the grill on the medium setting. Remove the foil from the roasting tin and shred the lamb with two forks. Place under the grill for about 4-5 minutes to crisp up.
Place the crispy lamb in the 8 lettuce leaves and serve with the cucumber sticks and shredded spring onion. You can serve with ready-made plum or hoisin sauce if wished (optional) and alter the calories accordingly.