My mom made longan tong sui, using a recipe from Rasa Malaysia.

The ingredients used were longan, red dates, ginko nuts, snow fungus, water, and rock sugar (rock candy). Longan tong sui is a sweet dessert soup, that can be served either hot or cold. When served cold, it’s very refreshing on a warm or hot day.

Below is some info about the dish, from Twinklestar:

Longan was known to invigorate the heart and spleen, nourish the blood and have a calming effect on the nervous system. It was also used as a remedy for stomachache, insomnia, amnesia, and dropsy. While white fungus said to be effective in nourishing the lungs, healing dry cough and clearing heat in the lungs. Those who have weak lungs catch cold easily. Eating stewed white fungus with rock sugar and red dates helps strengthen the respiratory system and thus, helps prevent cold.

Whereas, ginkgo was said to be one of the most effective medicinal herbs that are used in the treatment of memory loss. One of the most important benefits of ginkgo is the fact that it enhances the blood flow to the brain. As a matter of fact, it improves the circulation of the blood throughout the entire body. Other benefits of ginkgo biloba include neutralizing the free radicals which are substances that contributes in the development of heart diseases and cancer.

The other ingredients in this tong sui, red dates was also believed to have medicinal benefits. Red dates is sweet and warming, often used in enhancing and harmonizing the effects of herbs. Dates is used by Chinese to invigorate the spleen and stomach and is indicated for those with poor appetite, fatigue and loose stools. Chinese date also nourishes the blood and calms the mind.

And from Wikipedia:

Tong sui literally translated as “sugar water”, also known as tim tong, is a collective term for any sweet, warm soup or custard served as a dessert at the end of a meal in Cantonese cuisine. Tong sui are a Cantonese specialty and are rarely found in other regional cuisines of China. Outside of Cantonese-speaking communities, soupy desserts generally are not recognized as a distinct category, and the term tong sui is not used.