The "cake" was made from frozen fruit juice, sweet potatoes, carrots and sugar cane and it lasted about 15 minutes once giant panda mama Mei Xiang and her cub Xiao Qi Ji got hold of it.
The US National Zoo's most famous tenants had an enthusiastic breakfast in front of adoring crowds as the zoo celebrated 50 years of the Smithsonian Institute's panda exchange agreement with the Chinese government.
Xiao Qi Ji's father Tian Tian largely sat out the morning festivities, munching bamboo in a neighbouring enclosure with the sounds of his chomping clearly audible during a statement by China's ambassador in Washington, Qin Gang.
Mr Qin praised the bears as "a symbol of the friendship" between the nations.
Pandas are almost entirely solitary by nature and in the wild, Tian Tian would probably never even meet his child. He received a similar cake for lunch.
The event hailed the 1972 agreement sparked by Richard Nixon's landmark first visit by a sitting US president to communist China.
Mr Nixon visited China and met with chairman Mao Zedong, a key step in normalising relations between Washington and Beijing.
During the visit, Chinese premier Zhou Enlai gifted two pandas, Ling-Ling and Hsing-Hsing, as a gesture of goodwill to the American people.
The National Zoo celebration also highlighted the success of the global giant panda breeding program, which has helped bring the animal back from the brink of extinction.
Brandie Smith, director of the National Zoo, said the pandas "represent how great conservation outcomes can be achieved through great partnerships with our Chinese colleagues".
"Being able to introduce hundreds of millions of people worldwide to pandas and inspiring them to care about their conservation for five decades, coupled with our scientific breakthroughs, is a milestone truly worth celebrating," she said.
Pandemic panda birth a 'little miracle'
Xiao Qi Ji's birth in August 2020 was hailed as a near-miracle due to Mei Xiang's advanced age and the fact that zoo staff performed the artificial insemination procedure under tight restrictions shortly after the COVID-19 pandemic shut the entire zoo.
At age 22, Mei Xiang was the oldest giant panda to successfully give birth in the United States.
Normally, they would have used a combination of frozen sperm and fresh semen extracted from Tian Tian.
But zoo officials used only frozen semen in order to minimise the number of close-quarters medical procedures.
"It was definitely a long-shot pregnancy," said Bryan Amaral, the zoo's senior curator for mammals.
In honour of that long shot, the now 20-month-old cub was given a name that translates as "little miracle".
His mid-pandemic birth sparked a fresh wave of panda-mania, with viewership on the zoo's panda-cam live stream spiking by 1,200 per cent.
"I know how passionate people are about pandas," Mr Amaral said. "I'm not surprised by that passion at all."
Crowds started streaming straight for the panda section when the zoo opened at 8am.
Sisters Lorelai and Everley Greenwell, aged 6 and 5, ran toward the enclosure chanting "Pandas! Pandas!"
They watched the cub tumble around, try to wrestle his mum and tear the zero off the giant 50 emblazoned on the frozen cake.
"They knew this was coming," mother Kayleigh Greenwell said of her girls.
"We've been talking about it all week."
The zoo's original 1972 panda pair, Ling-Ling and Hsing-Hsing, were star attractions at the zoo for decades and became the longest-lived pandas in captivity, but panda pregnancies are notoriously tricky and none of their cubs survived.
Mei Xiang and Tian Tian arrived in 2000 and the pair has successfully birthed three other cubs: Tai Shan, Bao Bao and Bei Bei — also by artificial insemination.
All were transported to China at age four, under the terms of the zoo's agreement with the Chinese government.
Similar agreements with zoos around the world have helped revitalise the giant panda population.
Down to just over 1,000 bears in the 1980s, the species has since been removed from the lists of animals in danger of extinction.
AP/ABC
