Cut the fennel and parsnip into small cubes. Use a small melon baller to cut out the balls from the carrot. Blanch the snow peas in boiling salted water then place in ice-cold water for 2 minutes before draining through a sieve. Cut the snow peas lengthwise into thin strips. Place the remaining vegetables into boiling salted water for 2-3 minutes, drain through a sieve and briefly place in ice-cold water before draining again.
For the mayonnaise, all ingredients should be at room temperature. Pour the milk with honey mustard, saffron powder and a little sea salt into a tall blender jug and mix with a hand blender. Slowly mix in the oil in a thin stream and mix in the lemon juice last.
Cut the fish into pieces of equal size, remove the shells of the prawns, cut along the curve of the back with a sharp knife and remove the intestinal thread. Salt everything lightly.
Remove the crusts from the toast bread and fry in a hot pan with a little oil until crispy. Fry the fish and shrimps on both sides in a hot pan in 1-2 TBSP of oil and leave to stand in the pan for 1-2 minutes.
Pour the fish stock into a pot, bring to the boil and add the vegetables. Then season with sea salt.