Wash duck breasts, pat dry and scratch the skin crosswise. Heat a pan without fat. Sauté the duck breasts only on the skin side for about 5 minutes. Then sear on the meat side for 2-3 minutes. Season with salt and pepper. Cook the duck breasts for 15-18 minutes at medium heat.
Place croquettes on a baking tray and bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 15-20 minutes, turning once. Peel onion and cut into short strips. Melt clarified butter, add onion and sauté over medium heat for about 3 minutes until translucent. Add red cabbage and red wine, bring to the boil and braise over medium heat for about 10 minutes. Remove the duck breasts. Wrap in aluminium foil and let it rest for about 5 minutes. Pour plums into a sieve, collecting the juice. Skim the fat from the duck with a tablespoon. Bring the meat and plum juice to the boil, season to taste with salt, pepper and gingerbread spices. Stir in the sauce thickener and bring to the boil. Add the plums. Remove duck breasts from the foil and cut into slices.
Pour plums into a sieve, collecting the juice. Skim the fat from the duck with a tablespoon. Bring the meat and plum juice to the boil, season to taste with salt, pepper and gingerbread spices. Stir in the sauce thickener and bring to the boil. Add the plums. Remove duck breasts from the foil and cut into slices. Arrange on plates with sauce, red cabbage and croquettes. Sprinkle with cinnamon