A quarter of the fish arriving in the Aponiente restaurant's kitchen would be thrown away. Tonnes of waste every year. And instead of looking out at the horizon across the sea, as chef Ángel León is wont to do when he goes fishing, he decided to take a look at "where everything finishes, at the end of nature". He worked with his crew for two years "in silence", he confesses at Madrid Fusión Alimentos de España. "I decided to cook what nobody wanted". But there was only room for desserts on his menu. "What about turning it into desserts?" wondered León, with no clue about pastrymaking. "I'm a savoury kind of person, and I wondered whether a chef with three Michelin stars can be imperfect. Well, yes, he can, and there are a lot of things I don't know", he admitted during his ‘Marine offal’ talk with dessert chef David Gil, introduced as "a maestro, a genius, who worked with Albert Adriá". "That's where the madness comes from", he added.

The Puerto de Santa María team began their research with the skins of sea bass, moray eel, bream and bluegill, and developed a technique with a milk protein that removed the taste of fish, because they did not want any hints of the sea to reach diners' palates at the end of their meal. They used the skin to make "flutes of fish, with salt and sugar, dried out and boiled in sunflower oil, insufflating the skin to give it shape, and filling it with wafer cream", explained León. They used the same technique to turn moray eel skin into an "ice cream slice", after they had marinated it and cooked it with butter in a bag. "We make a sea bacon ice cream to fill up the ice cream slice we make from the eel", says León.

The next step was to work with fish scales to produce "scale pie", which melts in the diner's mouth. A "sea mochi" with milk and cinnamon, "with a spectacular crunchy texture along with soya ice cream. A wonderful recipe that will blow your mind", promised León, who continues to conduct research into scales as an ingredient for desserts. Red mullet scales, for example, form the basis of a frozen sponge with mullet roe.

More inventions. They use broken "puntillita" sections of baby squid, which can account for as much as 70% of each purchase, to make a croissant dough by way of a tribute to Puerto de Santa María's local pie, the "squid mille-feuille with butter cream". Squid also have a luminescent property, "a beautiful quality of their enzymes. We work with this protein to make Jules Verne's ‘20,000 leagues under the sea’ come true. The result is called ‘20,000 tongues under the sea’, and it is served with all the lights off to see the almond ice cream with the squid protein. In the dark we'll see diners' mouths full of sea luminescence" - this is León's dream for the season.

Another hitherto unthinkable discovery as a surprise served up this year by chef Ángel León is fish-eye popcorn. "Real fish eaters like us eat the eyes as well. But not many people like fish eyes. I wanted to do something new with the eyes, and so we use them. Sclerotics. When the eyes have been cleaned and dried, they turn into mouth-crunching popcorn. They don't taste of fish - they taste of popcorn. What we call ‘Sea popcorn’". When heated on stage, in fact, the white eye spheres begin to pop like maize kernels.

León and his crew did not stop there to rest. Their innovations produced caramel with fish collagen, sea crab tarts and invasive algae gumdrops, as desserts for the new season.