Peel, wash and cut the potatoes into corners. Put the potato wedges on a baking tray lined with baking paper and add a teaspoon of oil and some salt. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 18 to 20 minutes.
Wash and clean the celery stalks and cut them diagonally into slices. Wash the chicken fillet, dab dry and season with salt, pepper and paprika. Heat a teaspoon of oil in a frying pan. Fry the chicken filet on both sides for three to four minutes each.
Remove the meat from the pan, wrap in aluminium foil and keep warm. Add the celery to the pan and fry for two to three minutes. In the meantime, wash the apple, grate it dry, remove the seeds, cut into small cubes and add.
Mix two tablespoons of apple juice and starch. Deglaze the celery and apple with the remaining apple juice and simmer for one or two minutes. Stir in the starch, bring to the boil and season the sauce with salt, some paprika and pepper.
Wash the marjoram, dab dry and chop the leaves finely. Add the herbs to the sauce. Cut the chicken filet into slices and serve with the potatoes and the apple sauce.