For the chutney, cut the vanilla pod lengthwise. Scratch out the pulp. Wash, quarter and core the quince. Peel and dice the flesh. Boil up with 100 ml vinegar, sugar, 2 tablespoons honey, juice, oil, vanilla pulp and pod.
Cover and simmer for 35-40 minutes until the quinces are soft.
Peel onions and cut them into thin slices. Add to the chutney about 15 minutes before the end of the cooking time. Pour the chutney into a bowl and stir in mustard. Season with honey, vinegar, salt and pepper and remove the vanilla pod.
Preheat the oven for the duck breast (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Prepare the meat, brown. Season with salt and pepper and place the fillets in an ovenproof dish. Season with salt and pepper.
Cook in a hot oven for about 10 minutes. About 5 minutes before the end of the cooking time, brush the skin with 1 tablespoon of honey.
Take the meat out of the oven and let it rest in aluminium foil for about 5 minutes. Cut into slices and serve with warm chutney. Serve with focaccia and salad or fried hazelnut croquettes.