How long should deviled eggs marinate in the soy mixture?
Marinate the egg whites for at least 2–4 hours in the refrigerator for flavor to penetrate; overnight yields deeper soy flavor.
Can I make these ahead?
Yes. Marinate eggs up to 24 hours ahead, then fill and garnish with gochugaru and scallion just before serving to keep the filling creamy.
What is gochugaru and where do I find it?
Gochugaru is Korean red chili flakes with a mild heat and fruity flavor; find it in Asian markets, online, or substitute with a pinch of cayenne pepper or chili powder.
Can I use regular mayo instead of Japanese mayonnaise?
Regular mayo works, but Japanese mayo has higher egg yolk content and a richer, creamier taste that complements the soy umami better.
How many servings does this make?
This recipe yields 16 deviled egg halves, typically serving 4–6 as an appetizer or 8 as part of a larger spread.