Muñoz now has a dumpling and pasta restaurant, RavioXO, which opened in Madrid last year. He has a home-delivery service and food trucks brand called GoXO, which morphed into a fast-food venue in Barcelona in 2021.

Then there is the informal StreetXO, in Madrid, which he is expanding to Dubai in December, and to Barcelona and Miami next year. He is looking at proposals for Singapore and Tokyo.

His encounter with XO sauce – and more widely Chinese food – two decades ago helped spark the flame of what is now a culinary empire in the making.

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After completing catering college, the young Muñoz left the suburbs of Madrid for London. There he worked at trendsetting modern Asian restaurants including Hakkasan, Nobu and Nahm, as well as Locanda Locatelli.

He describes his time at Hakkasan as a “mind-blowing experience” because, at the time, no Spanish restaurants were creatively reworking Chinese food.

He visited Hong Kong and beyond, and the region made such an impression on him that he returned to Asia every summer for the next 15 years.

“The first time I went to Hong Kong, Bangkok and Singapore, I felt like I belonged there. I used to say that I was Chinese in another life,” he says with a smile.

Muñoz opened DiverXO (pronounced dee-ver-so) in 2007 in a humble, cramped site – it was a “little bit awful, actually”, he says.

Nevertheless, he quickly earned a reputation for his madly creative, no-boundaries cooking that combined Mediterranean and Chinese cuisines with inspiration from everywhere – “diverso” means diversity in Spanish.

Where an ingredient came from or how it was traditionally used was irrelevant; how it could be manipulated to create something never seen or tasted before was what fired Muñoz’s imagination.

He wanted not only to be original, but also to be avant-garde – to push boundaries or break them entirely.

Six years later, DiverXO (which had moved to a bigger space) was the only restaurant in Madrid with three Michelin stars, and Muñoz, then aged 33, was the second-youngest chef ever to earn such a coveted accolade.

While Muñoz’s obsessive drive to create something different was perhaps crystallised by his encounters with Asian food, the original trigger goes further back, to his childhood.

As a boy, every six months or so his parents would take him and his brother to a new restaurant in Madrid.

One birthday, they took him to Viridiana, where chef Abraham García cooked creative food drawing on a range of influences from around the world. It was a revelation that sparked a lifelong passion.

“That sensation of being in front of something new is my favourite feeling in life, I knew that even when I was 10,” says Muñoz in his heavily accented English.

“That’s what I want people to feel every time they come to my restaurant, that feeling of ‘wow’, like when you’re at a museum, or the theatre, and you see something new and you get butterflies in your stomach.”

The swarm of butterflies that decorate the ceiling at DiverXO, which has been in its third location since 2014, are a visual manifestation of this idea.

The ornamental pigs with wings, many of which imitate Muñoz by sporting a mohawk and studded neck collar, that are everywhere in the restaurant are a reminder of how far he has come.

When he told his father that he would one day own a famous restaurant that people would queue for, his father replied: “When pigs can fly.”

Since it was just six months old, DiverXO has had a long waiting list and it can take several months to get a table.

While Muñoz’s earlier career was defined by relentlessly hunting out inspiration from far and wide, now, at 43, he has a new regard for what is on his doorstep. He has created a role of food researcher at the restaurant with the aim of investigating little-known Spanish ingredients and using them in novel ways.

“Our approach changes all the time, and right now we’re wanting to ensure uniqueness along every step, from producer to plate,” he says. “Spain is so rich in ingredients, so we’re finding unique products from small producers and presenting them from a different point of view.”

Over the past year, he has reduced the use of salt in his dishes by 80 per cent, using the heat of 12 varieties of chillies and 15 kinds of Spanish citrus instead, which create a more “electrifying and exciting” flavour. He has cut down his use of sugar by almost 100 per cent.

Muñoz and his second wife, television personality Cristina Pedroche, have just had their first child. He is in therapy, he says, and he is happier, and more concerned with making his business better for the people who work with him.

“If you feel happy with life, you treat people around you better, and you’re a better professional.”

The softer heart within his punky public persona can also be found on the plate; some of his dishes conceal a haunting delicacy.

Take Invasive Species: Crab with XO Kimchi: it is a plate of spikes, with a stake rammed through the heart of three small straw­berries and balanced on the sharply pointed carapace of a blue crab.

Inside sits blue crab meat that has been cooked in palm sugar and rice vinegar brine, toasted shell oil, house-made iced kimchi and tomalley (crab fat) emulsion.

While the presentation is dramatic, the flavours are an act of sublime restraint. The strawberries, sourced from nearby Aranjuez, have been lightly barbecued, lending a caress of smoke to the sweetness, while the acid of the vinegar, the spice of kimchi and the umami of the crab harmonise into something more akin to a Shakespearean sonnet than a punk anthem.

Muñoz is also often whimsical. To complete his multi-course tasting menu, a selection of bon bons, described as “Soul Bonbon, Japanese Technique” are served on a circle of bright pink and black top hats that have wings or move up and down.

One of the sweets is a slightly squashed violet and blackberry mochi topped with a translucent purple shard of sweetness and purple petals – it is a girlie fantasy made real.

But to assume that the delicacy, the whimsy, and his growing maturity signal that Muñoz is losing his edge would be an error.

“Spanish Bull” involves drinking an incredibly rich, sour and spicy Galician ox bouillon from the horn of a bull, while “What Is the Best Part of a Rescoldo Stew? The Bottom-of-the-Pot Leftovers” includes a stew of mos rooster (an indigenous breed of Galician chicken) that has been reduced to the point of caramelisation and is intensely full-flavoured.

Muñoz’s appetite for risk and innovation also remains undiminished. Whereas another chef may choose this moment in their career when the accolades are streaming in to bask contentedly in the glory, Muñoz has big new plans for DiverXO. The restaurant will be moving next year to its fourth site.

The new restaurant, a “small house in a forest”, is now being built from the ground up in La Finca de Pozuelo, 20 minutes from Madrid. It will cover 2,000 square metres (21,527 sq ft) and seat 40 (up from 600 sq m and 36 covers at the present site), with three terraces and a huge kitchen. Final plans are still being drawn up, but it will be “less kitsch, but not less crazy.”

Muñoz sees the new venue as an opportunity to redefine the restaurant, the experience and the food. The avant-garde, by definition, breaks with precedent and is therefore constantly moving, so any chef wanting to stay at the vanguard needs to embrace change.

For Muñoz, reinvention has always been part of his DNA, and he relishes the challenge: “I want to create, conceptually, the best restaurant in the world,” he says. “I want people who’ve been to DiverXO to come to the new space and say, ‘What the f***, they’ve done it again’!”