Halve the prunes and soak in port wine for 1-2 hours.
Fry the duck breast fillets in hot oil for 3 minutes on each side, remove and fry in a preheated oven at 225 degrees for about 10 minutes.
Clean and wash the spring onions, cut into fine strips and sauté in the remaining frying fat. Add 3/8 l water, plums with wine and gravy and bring to the boil. Stir in the sauce thickener and cook for 1 minute.
Season the sauce with salt and pepper.
Cut the duck breast into slices and serve with the sauce.