Bring 2 l water, peppercorns and bay leaf to the boil. Peel the onion, cut into slices and add. Season with 2-3 tsp. salt. Wash chicken parts and simmer for about 1 hour. Let chicken cool down in the broth.
Wash the asparagus, cut off the woody ends generously. Clean, wash and halve the mangetouts. Steam asparagus in a little boiling salted water with 1 teaspoon sugar for about 8 minutes. Cook the sugar snap peas for about 4 minutes.
Quench everything and let it drip off.
Finely slice or grate the Parmesan cheese. Clean and wash lettuce and tomatoes. Cut lettuce into strips, halve tomatoes. Peel garlic, press through. Mix with mayonnaise and yoghurt. Season with salt, pepper, lemon juice and zest.
Remove meat from the broth. Remove meat from skin and bones, cut into small pieces. Mix with the yoghurt mayonnaise. Layer in a bowl (preferably made of glass) alternating with asparagus, mangetouts, tomatoes, lettuce and parmesan.
Allow to soak for at least 2 hours.