Step 1
Add the lamb, bicarbonate soda, garlic powder, caster sugar, and soy sauce to a bowl. Turn the lamb in the marinade to coat it evenly, and set aside on the bench for 30 minutes.
Step 2
Preheat the oven to 180C fan-forced (160C conventional).
Step 3
To make the black vinegar sauce, place the sugar, vinegar, water and soy sauce in a small saucepan. Simmer over medium heat for 15 minutes, or until the sauce has thickened slightly. Remove from the heat and allow it to cool. Once cool, stir through the cumin and Sichuan pepper.
Step 4
Divide the sauce into two small bowls. Add the spring onion and chopped coriander to one of the bowls only, and set both bowls aside.
Step 5
Thread the diced lamb onto skewers. Lightly oil a barbecue hot plate and cook the skewers for 2-3 minutes or until they start to brown. Spoon over the black vinegar sauce without fresh herbs and turn to coat. They should quickly caramelise.
Step 6
Transfer the skewers to an ovenproof dish and place in the oven for 5-8 minutes, or until the lamb is cooked to your liking.
Step 7
Transfer the skewers to a serving plate and spoon over the herby vinegar sauce. Serve while piping hot.
