Following up on Thailand's centuries-old relationship with Portugal, would there be any surprise that cultural exchange extended beyond religion and language to food?
There is a remarkable woman whose story is not well known outside Thailand: Maria Guyomar de Pinha or มารีอา กียูมาร์ ดึ ปีญา in Thai. Born in 1664 in the Siamese capital of Ayutthaya, Maria's family history is tied up with the history of Portugal's presence in Asia, from West to East. Her father Fanik Guyomar was from Portuguese Goa and of mixed Portuguese and Japanese descent. Her mother Ursula Yamada was from a Christian Japanese family that had emigrated to Siam after the Tokugawa Shogunate moved to ban Catholicism (introduced to Japan by Portuguese-sponsored Jesuits) starting in 1614.
Maria married a Greek adventurer, Constantine Phaulkon (Κωνσταντῖνος Γεράκης) from the Ionian Islands, who as a counsellor to King Narai of Siam became a wealthy nobleman in Ayutthaya. They had two sons, and the attachment to Portugal (rather than Thailand, Japan or Greece) can be seen in their names: Jorge and João.
The Phaulkon family experienced much drama during a turbulent time in Thai history, with growing French influence even leading to a Siamese revolution. Maria eventually became the head of the royal kitchen, and it was there that she secured her historical legacy.
She introduced many new desserts based on traditional Portuguese recipes, and with the use of egg yolks (which was not Thai practice before that), many of her creations took on yellow hues which visually pleased the Siamese aristocrats for the auspicious resemblance to gold. Obviously taste was also a winning factor as King Narai and his daughter Princess Sudawadi not only enjoyed but also recommended Maria's desserts to others, and many are still popular in Thailand today.
The use of egg yolks is part of the Portuguese tradition of conventual sweets, a by-product of the heavy use of egg whites for starching the often white clothing worn by nuns and priests. It is still debated whether all the different desserts attributed to Maria were actually invented by her, but foi thong (ฝอยทอง) was created by Maria from the Portuguese fios de ovos. Meaning "golden threads" in Thai, foi thong symbolizes a long life and undying love and is served as a dessert in auspicious ceremonies in Thailand.
As sign of Portugal's wider influence, versions of fios de ovos can also be found in Japan where they're called keiran somen (鶏卵素麺, "hen's egg noodle"), in Cambodia (vawee), and in Malaysia (jala mas, "golden net").