It did not turn out that way -- despite beginning with cheerful elbow bumps and birthday gifts for 66-year-old Angela Merkel, Germany's chancellor and a veteran of Brussels' conference rooms.

When the 27 leaders emerged into the dawn light on Belgium's national day on Tuesday to unveil their post-virus recovery plan, they had been locked in a formal summit for four days and nights -- more than 90 hours of horsetrading.

This made it the longest EU summit since the marathon meeting in Nice, France in December 2000, after which President Jacques Chirac declared: "It's not normal to finish at five in the morning."

Two decades later, summitry European-style had hardly changed, with EU leaders squabbling over a massive recovery fund to lift the European economy.

And it all began quite pleasantly.

When the summit started on Friday morning, Merkel, Europe's most powerful leader, received gifts of an Austrian torte, a favourite French white burgundy wine and a silver flask of rose oil from Bulgaria.

As the leaders removed their masks and sat down around a huge conference table in the European Council's Europa building, for a moment thoughts of recession or pandemic seemed far away.

But, as a grumpy Dutch premier Mark Rutte remarked two days later at a summit low point: "We're not here with the intention of meeting each other on our birthdays for the rest of our lives."

'At an impasse'

To be fair, he'd had a bad night, culminating with a harangue from a table-thumping French President Emmanuel Macron that caused him to worry the negotiations might collapse.

The first round of talks had been cordial enough.

Each leader delivered their vision of what was needed from Europe -- or not -- in an extra-large conference room usually reserved for EU-Africa summits, to allow for social distance.

The next day, the leaders got down to business with a new blueprint for the 750 billion euro package that -- if agreed -- would be a pioneering moment for the European unity project.

EU Council Chief Charles Michel hosted leaders in small groups or one-on-one on the terrace of his Europa Building HQ with its view over Brussels, lending the summit the air of a rooftop lounge.

But there was no spritz and pretzels as matters became increasingly tense and Rutte more entrenched in his low-spending position and insistence on austere labour-market reform.

"We are at an impasse. It's very complicated, more complicated than expected," admitted Italy's Giuseppe Conte.

As big powers France and Germany went into a duel with the "Frugals" -- Sweden, Denmark, Austria and the Netherlands -- the leaders of smaller neutral countries wandered off to buy chips.

Belgium's Sophie Wilmes and Luxembourg's Xavier Bettel appeared on Twitter in a sunny and festive Brussels square, and again later with the Estonian prime minister in tow for the city's favourite snack.

'Losing their cool'

Hours later, the first clash. Macron, fed up with the Frugals' refusal to buckle, was said to have ordered his staff to prepare the presidential jet to take him home to Paris.

Rutte, speaking to Dutch journalists, just shrugged it off and said he knew of no ultimatum.

As the hours ticked on through more bilaterals on Saturday, tempers frayed.

One diplomat complained that the "Frugals" were making behind-the-scenes warnings to the south that financial markets could react dangerously if they didn't cave.

At a dinner, Macron, irritated by three days of fruitless discussion, denounced those who "endanger the European project" through "selfishness".

Again he threatened to storm out of the negotiations, with French officials insisting Merkel was ready to leave too.

In the summit room, Macron, according to witnesses, attacked Austria's Kurz for leaving the meeting to make a call and accused Rutte of behaving like former British leader David Cameron -- whose strategy "ended badly".

At dawn on Monday, Kurz had his own take on Macron's aggressive stance.

"It's understandable that some people, when they don't get enough sleep, end up losing their cool," he said.

At 6am, the leaders ended up with their package, but were perhaps left wondering -- like Chirac, two decades ago -- whether there was some better way to reach an EU deal.

zap-arp/dc/kaf