A Fish That's Not Really A Fish...?!
Simmer the fish and potatoes in salted water, with the bay leaf and cloves. Chop the capers and olives. With a slotted spoon, remove the fish when still slightly undercooked, definitely before it begins to fall apart! Transfer to a bowl, remove skin and bones and flake into large pieces. When soft, drain and mash the potatoes, then add to the fish together with the olives, capers and parsley.
Meanwhile, slice the shallots and simmer them in the milk. Drain, adding the shallots to the mixture and reserving the liquid. Use the latter to make 3-4 tablespoons of bechamel sauce, which you will also incorporate into the fish mixture. Mix gently to avoid breaking up the fish and check for salt. Allow to cool.
Remove from the fridge, cut the pastry in the shape of your fish, after which brush the surface with the egg yolk beaten with a little milk.
With the tip of a knife draw the fish scales, the eye and any other detail, according to your imagination. The nicks are to be superficial and not go through the pastry. Bake in a preheated oven at 200C° for about 25 minutes or until the fish is nicely colored. P.s. if you wish, and have even more time and patience, you can make lots of individual small fishes, perhaps in different shapes.