Wash the duck and pat dry. Season inside and outside with salt and pepper. Wash thyme and shake dry. Orange wash, grate dry and chop 1 small. Put half of the thyme and orange pieces into the abdominal cavity. Close the opening with wooden skewers and kitchen string. Tie the legs together. Roast duck in an oiled roaster in a preheated oven (electric cooker: 225 °C/ convection oven: 200 °C/ gas: level 4) for about 2 hours
Peel 2 oranges thinly, squeeze the juice of one orange and cut the peel into thin strips. Peel the remaining orange so that the white skin is completely removed. Cut the fruit into slices. Bring the orange juice to the boil, briefly blanch the peel strips in it and allow to drain. Collect the juice
After about 1 hour, brush the duck with 1/4 litre of lightly salted water at intervals. Reduce the oven temperature 45 minutes before the end of the cooking time (electric oven: 175 °C/ gas: stage 2/ circulating air: 150 °C). Remove duck from the roaster and keep warm
For the sauce, pour the frying set into a pot and degrease. Add chicken stock, orange juice and orange jam, bring to the boil and simmer for about 10 minutes. Stir the starch and some water until smooth and stir into the sauce. Bring to the boil while stirring, season to taste with salt and pepper. Arrange duck and sauce and garnish with orange slices, zests and thyme