Wash the potatoes, cover and cook in plenty of boiling water for about 25 minutes. In the meantime wash chicken fillets, dab dry and cut into approx. 20 large pieces. Crumble toast finely.
Beat the eggs. Line a baking tray with baking paper and brush with oil. Season meat with salt and pepper, first in flour, then in egg and finally in breadcrumbs. Put the cutlets on the baking tray.
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 30 minutes. Turn over after half the baking time. (convection oven works especially well) Drain the potatoes, rinse them under cold water and remove the skin.
Cut the potatoes into slices. Peel and finely chop the onion. Boil up broth, onion, vinegar, some salt and pepper. Pour marinade over the warm potato slices, pull through and let cool down.
Remove the finished cutlets from the oven. Cut shish kebabs a little shorter and put 2-3 escalopes on each skewer. Keep warm if necessary. Clean, wash and drain the radishes.
Cucumber wash, peel. Slice the cucumber and radish into thin slices. Clean, wash and drain the rocket. Crème fraîche, some salt and pepper and mix together.
Mix cucumber, radish and rocket into the salad shortly before serving and season again with salt and pepper. Arrange potato salad on a large plate with warm or cold escalope skewers.
Serve garnished with lemon wedges and caper apples.