Bring the chicken stock and 600 ml water to the boil. Add the chicken fillets and cook over a low heat for about 20 minutes. Remove and allow to cool. Soak the gelatine. Cut meat into slices, peaches into wedges.
Cut two gherkins into compartments, the rest into slices. Pour chicken stock through a sieve and season with vinegar to taste very spicy. Squeeze the gelatine and dissolve in the warm broth. Pour a little stock into the bottom of a box mould (1 litre capacity) (pour a "mirror") and allow to set.
Line the bottom with cucumber compartments, peach slices, fillet slices and tarragon. Pile the remaining ingredients on top, fill up with stock. It is best to keep it cold overnight. For the sauce, peel garlic, press through a garlic press, mix with yoghurt and salad cream and season with salt, pepper and lemon juice.
Dip the aspic briefly in hot water and turn it over onto a plate. Pass the garlic cream to the aspic. Baguette tastes good with it.