“These are different [from local kumquats] – they are more sweet and the skin is soft. There is no bitter taste, and even two hours after eating it raw, I can still taste the citrus in my mouth,” he said.

Removing the seeds before using kumquat in dishes is tedious but worth the effort, and Chan has created a kumquat-themed afternoon tea set at the Four Seasons in Central, available until February 28.

Each item on the menu features the fruit, from savoury bites such as Balik salmon tartar with kumquat zest, and Bayonne ham with pickled kumquat on dark bread, to sweets such as sea salt milk chocolate kumquat confit truffle, and kumquat parfait – the filling like a frozen zabaglione in between crispy wafers. Even the jam for the scones is made from kumquat.

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Naohiko Fukada works in the agriculture and fisheries department of the Miyazaki prefecture government. He says the kumquats from this region are grown in greenhouses, and spend 210 days on the tree before harvest.

Seventy per cent of Japan’s kumquat production comes from Miyazaki. The kumquats grown there are also larger than average, thanks to the warm climate. The Miyazaki kumquats are available in supermarkets including City’super and Don Don Donki.

There are many ways to consume the kumquat, from drinks to desserts, and even in cocktails. Fukada enjoys kumquats daily, slicing them up to add to salads, or mixing them with soy milk, as the plant-based iron found in both the fruit and the milk makes it easier for the body to absorb Vitamin C.

He also likes to add sliced kumquats to hot water with black tea, ginger, and perhaps a little sugar or honey, for a soothing hot drink.

“You can eat up to 10 a day, but I like to eat five every morning. Each kumquat is 20 grams,” Fukada says through a translator.

Hong Kong-based traditional Chinese medicine (TCM) practitioner Cecilia Cheung Po-wan says at most one should eat five to six kumquats daily. She says they are a good aid for the respiratory system and help to nourish the skin.

“In Chinese medicine, foods we consider sour like kumquats are good for coughing, congestion, or when you have phlegm in your throat. The citrus in the kumquats acts like an astringent to calm down the inflammation,” she explains.

A good way to soothe the throat, she suggests, is to have honey and kumquat mixed with hot water – similar to Fukada’s version with tea, or to eat salted kumquat.

Cheung says the small fruit is high in fibre, which is good for digestion. “In TCM we consider it a warming food, so it helps with digestion. You don’t want to eat too many cold things, as it will slow down blood circulation.”

For a digestive aid, she suggests eating kumquats with cranberries or malt, while kumquats with pear juice can help nourish the lungs.

However, she warns diabetics not to eat many kumquats because of the high natural sugar content.

If you buy or receive a kumquat tree this festive season, don’t let its fruit go to waste. In Hong Kong it’s a custom to preserve kumquats in salt (or sugar) in a glass jar.

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Over time, the fruit’s juice is diffused into the salt to become a dark brown brine as the fruit becomes shrunken, wrinkled and brown. This preserved compote, which can last for years, is mixed with hot water as a remedy for sore throats and flu. Proof positive that this plant is pretty, propitious and practical.