Onsen Tamago – Japanese Hot Spring Egg

Onsen tamago is a traditional Japanese boiled egg which is originally slow cooked in the water of Onsen hot springs in Japan. The egg has a unique texture that the white tastes like a delicate custard (milky and soft) and the yolk comes out firm, but retains the colour and creamy texture of an uncooked yolk. The special texture is cooked by using the difference between the temperature of which the egg yolk and egg white solidifies. The egg is poached within the shell and is served with the shell removed in a small cup with sauce of broth and soy sauce.

General Preparation of Onsen Tamago

The traditional way of cooking onsen tamago is to place eggs into rope nets and leave them in a hot spring, with water that is approximately 70°C (158ºF) for 30 to 40 minutes. Crack open the shell and serve the egg in seasoned bonito dashi (Japanese stock) for breakfast, or in a light sauce made with mirin, dashi and soy sauce with chopped spring onions sprinkled over the top.

Onsen Tamago Salad with Silken Tofu
Cuisine: Japanese
Recipe type: Eggs
Prep time: 
Cook time: 
Total time: 
  • 1 box silken tofu
  • 4 large eggs
  • 1 tablespoon potato starch (or cornflour)
  • 1 tablespoon water
  • 2 teaspoons bonito flakes (katsuobushi)
  • 2½ tablespoons mirin
  • ¼ cup soy sauce
  • 1 tablespoon sake
  • 2 spring onions, finely chopped
  • 1½ tablespoons grated ginger
  • arugula
  1. Drain and wrap the tofu in paper towel. This will remove excess water. Cut into quarters and set aside.
  2. In a small-medium size pot, add 4 cups of water and bring to boil. When the water is boiling, turn off the heat and move the pot to a cool surface.
  3. Mix the potato starch with 1 tablespoon water, add to the pot and stir well.
  4. Gently put the eggs in the pot, cover and set the timer for 8 minutes.
  5. In four separate bowls, put arugula at the bottom and top with silken tofu.
  6. Make the tsuyu by combining soy, mirin, bonito flakes and sake. Microwave for a minute and set aside.
  7. When the eggs are done cooking, carefully transfer them in a bowl of cold water and let cool for a minute.
  8. Very gently break each eggs in a small bowl, then lay on top of each piece of tofu. This prevents the eggs from sliding to the bottom when breaking them right on top of the tofu.
  9. Add spring onions and ginger and finish by pouring a little tsuyu on top. Serve immediately.

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John Doe
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Born and raised in Dublin, Ireland, John is a superior specialist in growing palms and exotic plants.
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