1. Prepare Marinade: Mix together vegetable oil, crushed garlic, white pepper powder, crushed ginger, sugar, salt and 5 Tsp. of the sweet soy sauce.
2. Trim fat from the lamb and pierce with fork to ensure marinade will absorb into meat.
3. Marinate lamb evenly with marinade sauce and leave it in the fridge for at least 1 hour.
4. Place butter, Coca-Cola and lamb in a pressure cooker and cook for around 30 minutes or until tender.
5. Prepare Peanut Sauce: Stir together peanuts, shallots, chili paddies, lime juice and remaining sweet soy sauce.
6. Take meat out of the cooker and place in a baking tray.
7. Bake in 170-200 degrees oven for 15-20 minutes, or until golden and crisp at the outer.
8. Carefully remove meat from the pressure cooker and serve warm with peanut sauce.