Peel, wash and cut the potatoes into pieces. Wash duck breast, dab dry and rub with pepper. Heat 3 tablespoons of oil in a large pan and fry the duck breast in it. Fry over a low heat while turning for about 15 minutes. Add the potatoes and fry.
In the meantime, sort out watercress, wash and drain (simply cut off the cress from the bed). Clean, wash and cut the bell peppers into fine strips. Mix vinegar, salt, pepper and sugar. Beat the remaining oil into it and mix with the cress and paprika. Salt the duck breast, take it out of the pan and wrap it in aluminium foil, let it rest for a while. Pluck rosemary needles from the branch and chop them. Season potatoes with salt, pepper and rosemary and keep warm. Add chicken soup and sherry and bring to the boil. Stir in sauce thickener and bring to the boil again. Season to taste with salt and pepper.
Season potatoes with salt, pepper and rosemary and keep warm. Add chicken soup and sherry and bring to the boil. Stir in sauce thickener and bring to the boil again. Season to taste with salt and pepper. Cut duck breast into thin slices. Arrange on a plate with potatoes, salad and sauce. Garnish with rosemary