Thompson is specific about this historical lineage — he considers the Portuguese-Thai connection one of the most important and underdocumented influences in the development of the Thai sweet tradition. Egg-yolk-based sweets (fios de ovos in Portuguese, foi thong in Thai) are found wherever Portuguese traders and missionaries settled: Brazil, Macau, Japan (tamago somen), Cambodia, Vietnam, and Thailand. The shared ancestry across five countries is one of the more remarkable cases of culinary migration.
Two preparations from the Portuguese-influenced Thai court dessert tradition: foi thong — golden egg yolk threads, formed by drizzling beaten yolk through a fine-nozzled funnel or cone in spiralling patterns into simmering sugar syrup; and thong yib — small, pinched egg-yolk sweets cooked in the same syrup and formed into a lotus petal shape by pinching with the fingertips. Both preparations belong to the category of court sweets (khanom thai) whose origins Thompson traces to Maria Guyomar de Pinha, a Japanese-Portuguese woman who became the consort of the Greek adventurer Constantine Phaulkon at the Siamese court of King Narai (1656–1688) and is credited by Thai culinary tradition with introducing the egg-yolk-and-sugar sweet preparations of Portuguese colonial confectionery to the Thai court kitchen.
**The egg threads (foi thong):** - Egg yolks: 10, strained through a fine sieve to remove the membrane and produce a perfectly smooth, lump-free yolk liquid. - Sugar syrup: 500g white sugar + 500ml water + a few pandanus leaves, brought to a clear simmer. The syrup should be simmering steadily — not boiling vigorously, which would break the threads. - The drizzling device: traditionally a cone of banana leaf with a pin-hole; in practice, a squeeze bottle with a 1mm nozzle. **The technique:** 1. Drizzle the yolk through the cone/bottle in a thin, continuous stream over the surface of the simmering syrup — moving the cone in a steady, circular motion to produce the characteristic swirling thread pattern. 2. The yolk threads cook in the syrup within 60–90 seconds — they transition from bright orange-yellow to a deeper gold as the sugar penetrates. 3. Remove with chopsticks in a continuous motion, preserving the thread pattern. 4. Arrange in a portion or fold into a small mound. **The pinched sweets (thong yib):** - Same yolk mixture as foi thong. - Cooked in the syrup as small drops (not threads) — dropped from a cone into the syrup. - Removed when set. - Pinched while still warm with the fingertips into a lotus petal shape: thumb and two fingers, three pinches evenly spaced around the base, creating a tri-lobed shape. **[VERIFY]** Thompson's specific technique details — the cone dimensions, the syrup concentration. Decisive moment: The syrup temperature for both preparations — too hot and the threads break; too cool and they don't cook through and remain raw-tasting. Steady simmer throughout.
David Thompson, *Thai Food* (2002); *Thai Street Food* (2010)