Preheat the oven to 230°C (gas mark 7 or 8).

Place the puff pastry on a sheet of greaseproof paper on a baking sheet. Lower the oven temperature to 180°C (gas mark 6) and bake the pastry. After three to five minutes, it will start to puff up. Place a grill on top and continue cooking for 12-15 minutes. Leave to cool.
Meanwhile, remove the bones from the fresh fish and cut into 2mm slices.
Bring some salted water to a boil in a saucepan. Cook the fish for 30 seconds, and then remove and place on absorbent towels. Leave to cool.
Roughly chop the smoked trout, place in the bowl of a food processor with the soy sauce, paprika and softened butter. Blend until smooth.
Cut eight 9x3cm rectangles of puff pastry using a bread knife. Wash the apple but don’t peel. Cut a quarter of the apple into 1mm julienne strips and season with lemon juice.
Whip the cream and gently fold into the smoked trout mixture. Place in a piping bag with a 4mm smooth or ridged nozzle.

Assemble the millefeuilles by placing a rectangle of pastry on a plate, adding a layer of whipped trout cream, a few trout eggs and some strips of cooked trout. Repeat once.

Decorate the top with a few trout eggs and the strips of apple.