Preheat the oven to 200C / 392F and locate an oven proof frying pan and small saucepan.
In a small saucepan, combine all sauce ingredients. When adding the orange peel, twist it tightly to release the orange oil - this is how you get the flavour without the sugar!
Simmer the sauce over low heat for 20 - 25 minutes while preparing the duck. Whisk occasionally, taste for seasoning after 15 minutes.
To prepare the duck, combine the chinese 5 spice, salt and pepper. Score the duck skin in a criss-cross pattern, being careful to just cut through the fat like you would pork belly.
Rub the spice mixture all over the duck breast. Heat the oven proof frying pan over medium-high heat (with no oil) and then place the duck breast, skin side down.
Cook for 4-5 minutes then turn and cook for a further 2 minutes. A large amount of fat will come out - drain this off (keep it for future use though!)
Place the frying pan into the preheated oven and cook for 8 - 10 minutes until it reaches 57 - 60 degrees on a digital thermometer.
Remove from the oven and rest, tented with foil. Meanwhile, remove the orange peel from the sauce.
Serve with sauteed bok choy, cauliflower mash and fresh spring onion.