A novel approach to frying eggs using broth rather than fat has been gaining attention for producing a tender, softly cooked result. The method, developed after repeated experimentation inspired by Japanese onsen tamago, involves cooking eggs gently in a simmering mixture of broth, butter, soy sauce, and mirin, rather than the more traditional technique of frying eggs in oil or butter.

The technique emerged somewhat serendipitously during a dinner preparation, when the cook sought an alternative to the usual approach of covering the pan to steam eggs or repeatedly spooning hot fat over the whites to cook them through. Drawing from experiences in Kyoto, Japan, where onsen tamago—eggs slow-cooked in their shells in hot springs and served in a flavorful broth—were consumed frequently, the cook sought to recreate a similar texture and flavor at home.

Japanese onsen tamago involve precise timing to achieve a softly set egg white and creamy yolk, a balance that can be difficult to replicate. Early attempts included cracking eggs into a bowl and gently pouring hot water over them before microwaving to achieve a soft consistency. This was often accompanied by adding Hondashi, an instant bonito-flavored soup stock, to create a warm broth that complements the eggs.

The current iteration of the method involves simmering eggs directly in lightly seasoned broth infused with butter, soy sauce, and mirin. This approach keeps the eggs from sticking to the pan and results in a lusciously soft texture, as water-based cooking gently coagulates the proteins, similar to poaching but with added savory elements. The process of spooning the broth over the eggs during cooking—known as basting—helps achieve a custard-like softness.

This broth-basted egg draws culinary parallels to the softly cooked eggs found in traditional Japanese dishes such as oyakodon, a chicken and egg rice bowl, or the soy sauce-seasoned eggs often served atop ramen bowls. It presents a contrast to eggs cooked directly in fat, which develop firmer whites and more pronounced edges.

The broth-basting technique offers a straightforward, less hands-on alternative to steaming or fat-basting, delivering a tender egg with layers of umami-rich flavor. By combining a simple cooking liquid with gentle heat, this method provides a comforting, home-style variation on sunny side up eggs that has resonated with those seeking both delicacy and depth in a familiar dish.