Preheat the oven to 180'C.
Cut the puff pastry into rectangles (5cm x 3cm). Allow 3 per person.
Bake two thirds of the puff pastry rectangles for 15 minutes with another baking tray on top to keep them flat. Bake the rest uncovered and allow them to puff up.
When golden brown allow to cool.
Increase the oven temperature to 220'C.
Take all the vegetables and, using a brush, coat with a thin layer of olive oil. Place them in a baking tray and roast the vegetables for 40 minutes. Remove the aubergine, pepper, and tomatoes and set aside. Leave the onion in the oven for another 15 minutes until it too is soft. Remove and set aside.
By now the skins of the vegetables will be soft and loose. When cool enough to handle, peel the skins off the vegetables. Seed the pepper and remove the stalk. Remove the top of the tomato and the aubergine with a knife.
Using your hands, tear the pepper into strips and the tomato into three or four pieces. Do the same with the aubergine. With a knife, slice the onion into rings.
Mix the vegetables together and place them in a serving dish. Cover them with the remaining olive oil and the sherry vinegar. Sprinkle with salt and pepper.
Reduce the oven temperature to 180'C.
Wash the mackerel, remove the guts but keep the fish whole. Chop the rosemary and zest the lemons. Mix this into the salt.
After cleaning the fish, take an oven tray big enough to accommodate the fish and sprinkle a thin layer of the coarse salt on the bottom. Place the fish on top and cover completely in a thick layer of salt. Bake for 8 minutes and then remove from the oven. Allow to cool slightly and then remove the salt crust and the skin of the mackerel. Flake the flesh and keep to one side.
Cover the bottom layer of pastry with vegetables and a layer of mackerel meat and then place another layer of pastry on top. Add another layer of vegetables and fish, then place the final layer of puffed pastry on top.
Serve with a drizzle of balsamic vinegar and pea shoots.
«Vary the fish in this recipe by using whole sea bass or sea bream.»