Two preparations made entirely from strained egg yolks and sugar syrup — foi thong (golden threads, made by passing the beaten yolks through a fine-holed implement into boiling syrup to produce golden threads) and thong yib (golden flowers, made by dropping beaten yolks into hot syrup through a mold to produce petal-shaped sweets). Both are among the most technically demanding of all Thai desserts and are attributed to the Portuguese-Japanese court influence of Maria Guyomar de Pinha in the Ayutthaya court (17th century). Thompson treats them as ceremonial preparations — made for weddings, festivals, and royal presentations.
**The egg yolks:** Duck egg yolks only — their deep orange colour is the entire visual appeal of these preparations. Strained through a fine sieve to remove any membrane or chalaza. The strained yolk should be pure, uniform, and deeply coloured. **The sugar syrup:** - White sugar dissolved in water to a thin syrup — approximately 220g sugar per 250ml water, heated to 105°C (a thin syrup, not caramel). - Flavoured with pandan leaf (Entry TH-59) or jasmine water: the fragrance infuses the syrup and therefore the finished preparation. **Foi thong (golden threads):** A small jug of strained yolks is drizzled in a continuous thin stream into the simmering syrup — the yolk sets instantly on contact with the hot syrup into a fine, delicate golden thread. The drizzling motion produces parallel threads. These threads are then carefully lifted from the syrup, formed into bundles, and arranged. The technique requires a steady hand and confidence — the thread must be continuous and of even thickness. **Thong yib (golden flowers):** A small amount of strained yolk is dropped into the hot syrup through a 5-petalled mold — the yolk sets immediately in the petal shape and is lifted from the syrup with a small spoon or spatula. Decisive moment: The temperature of the syrup — and maintaining it throughout the preparation. At 105°C: the yolk thread sets immediately and holds its shape while remaining tender. Below 100°C: the yolk sinks and spreads rather than setting in threads. Above 110°C: the thread sets too hard and lacks the characteristic tender, slightly sticky texture.
David Thompson, *Thai Food* (2002); *Thai Street Food* (2010)