On the streets of Danang, Vietnam, large, alabaster-hued eggs simmer next to low tables. A late-night muncher takes a seat on a stool while the vendor busies herself piling pickled papaya in small bowl, ladling gingered fish sauce over the julienned strips before sprinkling the composition with crushed peanuts. She places the bowl on the table next to a plate of verdant leafy greens, then returns with an egg perched atop a small cup. The expert eater takes a spoon and taps the shell’s dome until she can break and lift the lid, revealing the savory soup within. Suspended in the liquid is a premature duckling. Pulling out a spoonful of broth and tender duck, the diner garnishes the morsel with greenery and sauce, creating the perfectly balanced bite of rich duck, brightly-sour sauce, and freshly-flavored herbs. 

While the Philippines is often cited as the epicenter of broth-filled fertilized duck eggs with their popular balut, Vietnam has its own delicious version of this beloved food. Trứng vịt lộn or hột vịt lộn, roughly translated to “duck egg” or “duck flavor,” is a street-side snack, and unique regional preparations range from North to South. Similar to the Philippine preparation, Vietnamese vendors purchase the fertilized eggs shortly after they’ve been laid, then allow them to gestate. Over the course of about two weeks, the yolk and albumen take on an increasingly gamey flavor and structure, which chefs halt by cooking the egg before the fetus becomes too crunchy (and feathered).

Throughout Vietnam, trứng vịt lộn customarily comes with salt, pepper, and a side of rau răm, a fresh-flavored Vietnamese green that is at once likened to mint, coriander, and cilantro. In the North, diners peel the eggs, serving the veiny orbs in bowls with simple sides of greens. In the South, however, the eggs are commonly perched atop small egg cups, and served with the likes of citrus, ginger, pickled papaya, and vinegar-based sauces featuring fish sauce and spicy peppers. North or South, the Philippines or Vietnam, don’t knock this fertilized egg unless you’re trying it.