Prepare the jelly as indicated on the sachets, but with only 75 cl of water.
Cook the quail eggs for 3 minutes in boiling water so that they are soft, immerse them in cold water and peel them. Pour a little jelly into the bottom of a savarin mold and place it in the fridge.
Cut the cucumber in half lengthwise and form strips with a paring knife, blanch them for 3 minutes in salted boiling water, refresh them under cold water and drain them thoroughly.
As soon as the jelly has set at the bottom of the mould, lay in successive layers 10 quail egg halves, cut side down, strips of cucumber and salmon, then tarragon and dill leaves.
Pour a little jelly, add the rest of the salmon, cucumber and quail eggs. Season with pepper, fill with jelly and chill for at least 4 hours.
Whip the Chantilly cream, gradually add the horseradish, salt and pepper and set aside in the fridge.
To serve, immerse the bottom of the mold for a few moments in lukewarm water, unmold the crown on a dish, place the cream in the center and decorate with salmon eggs.