Onsen Tamago is a traditional Japanese dish made by slow-cooking eggs in hot spring water. The cooking method results in a unique texture, where the egg white becomes silky and the yolk remains creamy. This gentle cooking process is typically done at temperatures around 70°C (158°F) for about 30 to 40 minutes. Often served as a side dish or topping, Onsen Tamago is commonly enjoyed with rice, soy sauce, or dashi. The dish is popular in Japan, especially in regions known for their onsen (hot springs), where the natural geothermal heat is utilized for cooking.