Onsen Tamago: The Ultimate Japanese Soft-Cooked Egg

Healthy Japanese Onsen Tamago Recipe with Savory Soy Broth

Discover the silky, custardy perfection of onsen tamago – a Japanese delicacy that will elevate your egg game to new heights. This traditional soft-cooked egg, served in a savory soy-dashi broth, offers a sublime texture and flavor that will transport your taste buds straight to Japan.

Unlocking the Secrets of Onsen Tamago

Onsen tamago, literally “hot spring eggs,” originated in Japan’s geothermal baths. Today, you can recreate this culinary magic in your own kitchen, no hot springs required! Our method uses precise temperature control to achieve that signature silky texture – a tender white encasing a lusciously warm, custardy yolk.

Master the Art of Temperature Control

The key to perfect onsen tamago lies in maintaining a steady 167°F (75°C) water temperature for exactly 13 minutes. This creates a gentle heat gradient, resulting in eggs with slightly firmer whites and gloriously runny centers. While an immersion circulator is ideal, we’ll show you how to achieve great results with just a pot and a thermometer.

The Perfect Pairing: Umami-Rich Soy-Dashi Broth

Elevate your onsen tamago experience with our balanced soy-dashi broth. This savory elixir combines dashi (Japanese smoked-bonito and kelp stock), soy sauce, and mirin in perfect harmony. The result? A flavor profile that perfectly complements the delicate eggs.

Onsen Tamago (Japanese Soft-Cooked Egg With Soy Broth)


For the Eggs:

  • 4 large eggs

For the Broth (optional; see notes about substituting instant dashi):

  • 2 tablespoons (30ml) mirin
  • 2 teaspoons (8g) sugar
  • 1/2 cup (120ml) soy sauce
  • 3/4 cup (180ml) homemade or instant dashi
  • Thinly sliced scallions, for garnish


  1. For the Eggs (Immersion Circulator Method): Set your immersion circulator to 167°F (75°C). Once the water reaches temperature, gently lower in the shell-on eggs and set a timer for 13 minutes. When time’s up, transfer eggs to an ice bath to halt cooking. Pro tip: You can refrigerate the eggs, unpeeled, for up to 2 days.
  2. For the Eggs (Stovetop Method): Fill a large pot with water and heat to 167°F (75°C), monitoring with an instant-read thermometer. Add the eggs and maintain temperature for 13 minutes, adjusting heat as needed. Don’t stress if the temperature fluctuates slightly – just aim to stay close to 167°F. After cooking, plunge eggs into an ice bath. Store refrigerated, in-shell, for up to 2 days.
  3. Crafting the Soy-Dashi Broth: While the eggs cook, create your kaeshi (soy-mirin concentrate). Simmer mirin in a small saucepan, then dissolve in the sugar. Add soy sauce, bring to a simmer, then remove from heat. Cool this magical elixir in the refrigerator.
  4. When ready to serve, combine 1/4 cup of your cooled kaeshi with 3/4 cup dashi. This ratio creates the perfect balance of flavors, but feel free to adjust to your taste. Bonus: Extra kaeshi mixed with dashi makes an excellent cold dipping sauce for soba or udon noodles!
  5. Time to plate! Carefully crack each egg into a small bowl. Using a spoon or clean paper towel, gently separate the perfectly cooked egg from any loose whites. Slide each egg into individual serving bowls, pour the aromatic broth around it, and crown with a sprinkle of vibrant green scallions. Prepare for a moment of culinary bliss!


These versatile eggs aren’t just for solo enjoyment – try them atop steaming rice bowls, swimming in a rich ramen broth, or as a luxurious addition to any Japanese-inspired dish. The possibilities are endless!

Short on time? Instant dashi works beautifully in the broth recipe. Don’t be afraid to experiment with the soy-mirin concentrate to dashi ratio. Use more dashi for a lighter touch, or amp up the concentrate for bolder flavors.

Nutrition Facts (per serving)
73 Calories
5g Fat
1g Carbs
6g Protein
Nutrition Facts
Servings: 4
Amount per serving
Calories 73
% Daily Value*
Total Fat 5g 6%
Saturated Fat 2g 8%
Cholesterol 186mg 62%
Sodium 72mg 3%
Total Carbohydrate 1g 0%
Dietary Fiber 0g 0%
Total Sugars 0g
Protein 6g
Vitamin C 1mg 4%
Calcium 31mg 2%
Iron 1mg 5%
Potassium 79mg 2%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.

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