Press Saute on the Instant Pot on Less and add powdered rock sugar and 2 tbsp water.
Increase heat to Normal and boil without stirring until medium caramelised. Press Cancel and add 1 cup of water (mixture will spit). Stir over heat until smooth.
Add 5-spice powder, garlic, galangal, soy sauces, star anise and cinnamon. Then place in the whole duck. Add enough water to cover about halfway up the duck pieces.
Press Saute again and bring to simmer for 5 minutes, skimming any scum and access oil that comes to the surface.
Press Cancel and close the lid. Press Poultry and select Pressure Level High. Adjust time to 40 minutes.
Once done, natural release pressure and take out the duck from the Instant Pot.