Onsen Egg (Japanese Slow-Cooked Egg): Perfectly Soft, Silky, and Delicate

The Onsen egg is a traditional Japanese delicacy, renowned for its incredibly soft, silky texture and delicately poached yolk. The name “onsen” means hot spring, as these eggs were originally slow-cooked in the waters of Japan’s natural hot springs. The process results in an egg that’s half-cooked with a firm white and a rich, creamy yolk, making it a versatile ingredient in various dishes. Whether served over rice, in ramen, or simply with soy sauce, Onsen eggs are a simple yet elegant addition to any meal.

Origin and Inspiration

Onsen eggs originated in Japan, where the unique method of cooking eggs in geothermal hot spring waters became popular. Traditionally, eggs were left in the warm spring waters for extended periods, allowing them to slowly cook to perfection. The result is a soft poached egg where the whites are set, but the yolk remains custardy and luscious. Today, Onsen eggs are a popular feature in Japanese cuisine, often served in restaurants or at home over rice or as a topping for various dishes.

Nutrition Info (Per Serving)

Calories: 70 kcal | Carbohydrates: 1g | Protein: 6g | Fat: 5g | Saturated Fat: 1.5g | Cholesterol: 185mg | Sodium: 65mg | Potassium: 70mg | Fiber: 0g | Sugar: 0g

Ingredients (2 Servings)

• 2 large eggs
• Water for cooking
• 1/4 cup soy sauce
• 1/4 cup mirin (optional)
• Chopped green onions (for garnish)
• Sesame seeds (for garnish)

Instructions

1. Heat the Water:
   Fill a pot with enough water to fully submerge the eggs. Heat the water to 167°F (75°C) using a thermometer to monitor the temperature. Onsen eggs need to cook in precisely warm water to achieve the signature silky texture, so maintaining this temperature is crucial.
2. Cook the Eggs:
   Gently place the eggs into the water. Keep the water at a steady temperature of 167°F (75°C) for 12-14 minutes. During this time, the eggs will slowly cook, ensuring the whites are set but the yolks remain soft and creamy.
3. Prepare the Sauce (Optional):
   While the eggs are cooking, prepare a simple sauce by combining soy sauce and mirin in a small bowl. This sweet and salty mixture can be drizzled over the eggs for added flavor.
4. Chill the Eggs:
   After cooking, remove the eggs from the water and place them in an ice bath for 1-2 minutes to stop the cooking process. This will also make it easier to peel the eggs.
5. Serve:
   Carefully crack open the eggs and gently place them over rice, in a bowl of ramen, or on a plate. Drizzle with the soy sauce mixture and garnish with chopped green onions and sesame seeds for added flavor and texture.

What Does It Pair Well With?

• Rice: Onsen eggs are commonly served over a bowl of warm rice, creating a simple but comforting meal. The egg’s creamy yolk mixes beautifully with the rice, adding richness.
• Ramen: Add an Onsen egg to your bowl of ramen for a luxurious, silky texture that complements the broth.
• Salads: Onsen eggs also pair well with green salads, offering a creamy element that enhances the freshness of the vegetables.

What is the Shelf Life?

Onsen eggs can be stored in the refrigerator for up to 2 days if left in their shells. If you plan to use them later, simply reheat them in warm water (around 140°F/60°C) for 5 minutes to bring back the perfect texture.

Alternative Cooking Methods for Onsen Eggs

1. Sous Vide (148°F/64.5°C for 45 minutes)

This method results in a slightly firmer egg white while maintaining the rich, creamy yolk. Perfect if you prefer a more structured white with the same delicate yolk.

2. Sous Vide (167°F/75°C for 12-14 minutes)

This is the classic sous vide method that gives you silky whites and a custard-like yolk. The higher temperature for a shorter time creates an egg that is delicate and luxurious, ideal for topping rice or ramen.

3. Steaming

To steam Onsen eggs, bring water to a simmer and place the eggs in a steamer basket. Steam the eggs for about 12-14 minutes, being careful to maintain a consistent temperature. This method mimics the slow cooking process of traditional hot spring eggs but requires more attention to the temperature.

4. Hot Water Bath (Stovetop Method)

If you don’t have sous vide equipment, you can cook Onsen eggs using a stovetop water bath:

• Heat water to 167°F (75°C) and maintain this temperature.
• Cook the eggs for 12-14 minutes.
  Using a thermometer to keep the water at a stable temperature is crucial for achieving the perfect Onsen egg texture. This method replicates the experience of cooking eggs in a Japanese hot spring.

5. Pressure Cooker (Instant Pot)

If you’re using a pressure cooker, you can cook Onsen eggs by setting the Instant Pot or pressure cooker to low pressure. Cook the eggs for 3 minutes, then let them naturally release the pressure for 10 minutes before placing them in an ice bath. This method creates a soft, delicate egg with minimal effort.

6. Minimal Water and Gas Method (จาก YouTube: วิธีต้มไข่แบบประหยัดน้ำประหยัดแก๊ส)

This method uses minimal water and gas:

1. Place room temperature eggs in a pot. Add just enough water to cover the bottom of the pot by about 1 cm.
2. Bring the water to a boil using medium heat.
3. Once boiling, cover the pot with a lid and let the eggs boil for 4 minutes.
4. Turn off the stove but keep the lid on. Let the eggs sit covered for 3 minutes for a runny yolk or 5 minutes for a firm yolk.
5. This energy-efficient method produces eggs with bouncy whites and easily peelable shells.

7. Microwave Poached Egg

1. Crack an egg into a microwave-safe bowl or cup.
2. Add 1/2 cup of water over the egg.
3. Cover with a microwave-safe plate and microwave on high for 45-60 seconds.
4. Gently remove the egg and serve. This quick method creates a soft poached egg with a runny yolk.

8. Oven-Baked Eggs

1. Preheat the oven to 350°F (175°C).
2. Grease a muffin tin and crack an egg into each cup.
3. Bake for 10-15 minutes depending on your desired doneness.
4. These eggs are perfect for breakfast sandwiches or as a side dish.

9. Coddled Eggs

1. Grease a coddler and crack an egg into it.
2. Submerge the coddler in simmering water.
3. Cook for 5-7 minutes for a soft egg or up to 10 minutes for a firmer texture.
4. Serve the egg in the coddler for a more elegant presentation.

10. Boiling in Cold Water

1. Place eggs in a pot of cold water, enough to cover the eggs.
2. Slowly bring to a boil. Once boiling, remove the pot from heat and cover with a lid.
3. Let the eggs sit for 4-5 minutes for a runny yolk or 8-10 minutes for a firm yolk.
4. Transfer to an ice bath to stop cooking and make peeling easier.