Ingredients:

  • 4 Large Eggs (must be fresh, refrigerated)
  • 5 Litres / 10 cups Boiling Water (for the bath)
  • 2 Litres / 8 cups Cold Water (for the bath)
  • 60 ml / 1/4 cup Dashi Stock (or low-sodium vegetable stock)
  • 30 ml / 2 Tbsp Soy Sauce (preferably Japanese shoyu)
  • 30 ml / 2 Tbsp Mirin (Japanese sweet rice wine)
  • 5 ml / 1 tsp Caster Sugar (superfine sugar)
  • A pinch of Shichimi Togarashi
  • Finely Chopped Spring Onion or Chives

Instructions:

  1. Prepare the Bath Water: Combine the specified amounts of boiling water and cold water in your insulated container (cooler or thermos).
  2. Achieve Target Temperature: Using a reliable digital thermometer, stir the water until the temperature stabilizes at 64°C (147°F). Start slightly higher than 63°C, as the cold eggs will cause an immediate dip.
  3. Place the Eggs: Carefully lower the four cold eggs directly into the 64°C water bath. Ensure the eggs are fully submerged.
  4. Seal and Cook: Immediately close the insulated container tightly. Set a timer for 40 to 60 minutes, depending on desired white firmness (40 mins for softer, 60 mins for firmer).
  5. Maintain Temperature Check (Optional but Recommended): If using a less effective container, quickly check the water temperature after 15 minutes. If it has dropped below 61°C (142°F), quickly add a tiny amount of hot water to bump it back up to 63°C, stirring gently before resealing.
  6. Prepare the Tsuyu Sauce: While the eggs cook, combine the dashi, soy sauce, mirin, and sugar in a small saucepan. Bring to a gentle simmer over medium heat until the sugar dissolves. Remove from heat and allow to cool slightly.
  7. Stop the Cooking: Once the cooking time is complete, immediately transfer the eggs from the hot bath to a prepared ice bath for 5 minutes. This halts the cooking process.
  8. Serve: Carefully crack each Onsen Egg into a small serving bowl. The white should hold its shape slightly, and the yolk should be viscous. Drizzle generously with the prepared Tsuyu sauce and garnish with spring onions and a sprinkle of Shichimi Togarashi.