Dashi-Steamed Egg Custard

Ingredients

• 8 dried shiitake mushrooms
• ½ white or yellow onion, thinly sliced
• 5 garlic cloves
• 4 4×4" pieces kombu
• 2 scallions
• 5 large eggs
• Kosher salt
• Crushed toasted nori sheets (for serving)

Steps

1. Bring mushrooms, onion, garlic, kombu, and 2 quarts water to a simmer in a large saucepan over medium-high heat. Cook, reducing heat as needed to maintain a simmer, 30 minutes.
2. Strain dashi through a fine-mesh sieve into a large bowl (or an airtight container if not using right away) and let cool.
3. Do Ahead: Dashi can be made 1 week ahead. Cover and chill.
4. Separate dark green tops from scallions; thinly slice both parts and set aside separately. Gently whisk eggs in a heatproof ceramic bowl that can hold at least 3 cups water (a pair of chopsticks are the ideal whisking tool since they fully incorporate the eggs without introducing too much air). Add ¾ cup cooled dashi and season with salt (you’ll need about ½ tsp. kosher salt, as the dashi is unseasoned). Stir in reserved scallion whites and pale green parts.
5. Place bowl inside a large saucepan with a tight-fitting lid. Pour in water to come two-thirds up the sides of the bowl. Cover saucepan and set over medium-high heat. Bring water to a boil. Reduce heat and simmer until eggs are just set (they will still wobble slightly when gently wiggled), 18–25 minutes.
6. Serve eggs topped with crushed nori and reserved scallion greens.