Wash potatoes thoroughly and cook in boiling water for 35-40 minutes. Drain and allow to evaporate. Cut potatoes in half lengthwise and hollow them out with a small spoon
Grease a large ovenproof dish. Put potato halves in it, season with salt and pepper. Carefully break 1 egg into a small bowl and place it in one half of the potato. Fill the remaining potatoes in the same way. Let it set in the preheated oven (electric cooker: 175 °C/ circulating air: 150 °C/ gas: see manufacturer) for about 10 minutes
In the meantime, clean the salad thoroughly, wash and drain well. Wash, clean and quarter the tomatoes, remove the seeds. Cut quarter into small pieces. Clean, wash and cut the peppers into fine strips. Put 60 g of potato interior (use the rest for other purposes / e.g. fry with bacon and onions) in a bowl and mash with a fork. Mix in mustard and vinegar. Fold in the oil bit by bit. Season with salt, pepper and sugar
Mix lettuce, tomatoes and peppers. Cut some cress from the bed. Arrange 2 potato halves and salad on plates. Drizzle with some dressing. Garnish with cress. Add the rest of the dressing