But at 80, he is still busy dishing out hundreds of his signature tempeh patties and burgers every month.

“Age is never a stumbling block for me. I will keep serving people healthy, delicious tempeh food,” he told the Post.

Tsui was among the participants at this year’s Vegetarian Food Asia event, held from February 17-19 at the Hong Kong Convention and Exhibition Centre.

The three-day showcase attracted 600 brands covering vegetarian, vegan, green living, natural and organic products, with more than 5,000 types of food, products and services on display.

Tsui, who was born in Guangdong in 1943, moved to Hong Kong alone at the age of 14 and worked in several jobs before he discovered his calling in his 20s.

He learned to cook Russian and French cuisine in different restaurants before he moved to Guam, a United States territory in the western Pacific, in 1984 with his wife and two children to seek new opportunities.

Tsui and a partner opened a restaurant serving mostly vegetarian food in 1995 and it was there that an American customer introduced him to tempeh, which sparked a new food passion.

A versatile source of vegetarian protein, tempeh is made from fermented soybeans that are pressed into a dense cake. It can be sliced and deep-fried, cubed and cooked with herbs and spices or mixed with vegetables and tofu.

It has turned up on Western restaurant menus too, prepared in a variety of ways as a substitute for meat.

Tsui, a Buddhist and mostly vegetarian, carried out research and experimentation before he served his first dish of stir-fried broccoli with tempeh at the restaurant.

It proved popular and he was encouraged to do more.

He said: “It is the safest, most nutritious and cheapest vegetarian food.”

Tsui returned to Hong Kong with his family and worked at restaurants in the city and also in the US after his partner decided to sell the Guam restaurant in 1997.

He opened a takeaway in Central called Tempeh Foods in November 2019, at the age of 76, serving Western-style burgers, salad and pasta featuring his favourite ingredient.

Tsui said expatriates and locals liked the food, but Covid-19 arrived and the business was hit hard.

Unable to pay the monthly rent of about HK$40,000 (US$5,095) for his 200 sq ft unit and staff wages, he shut down in April 2021.

That was a blow, but he was not ready to give up yet. Instead, he took his handmade tempeh treats online.

Tsui has worked one or two days a week at Cook Beyond, a co-working place for chefs, since last year, preparing tempeh meals, sauces and snacks he sells on his Facebook page.

His baked tempeh patties and burgers are the most popular items and he sells about 100 a week. Each patty sells at HK$20 and a tempeh burger is HK$48.

His burger consists of a savoury patty in a bun, topped with lettuce, tomatoes and apple sauce.

Tsui said he did everything himself, including deliveries. “I’m a one-man band,” he laughed.

But, even after all this time, he said tempeh was still unfamiliar to many Hongkongers.

“Hong Kong is a conservative city in terms of food,” he explained. “It takes a long time for new things to be accepted.”

But, ever the optimist, he said his next goal was to attract investment to start a factory to mass produce tempeh products for catering businesses and individual customers.

“I hope my tempeh food will make people healthy,” he said. “That is why I’m still doing this at this age.”