Can I use regular mayonnaise instead of Japanese mayo?
Regular mayo works but will taste less rich and tangy. Japanese mayo (Kewpie) has higher egg yolk content and adds deeper creaminess that defines this dish.
Should the egg be cooked or raw?
Either works. A soft-boiled or poached egg (2–3 minutes in the hot broth) creates a creamy sauce; a raw egg stirred in immediately cooks from residual heat.
How do I prevent the mayo from curdling?
Stir the mayo into the cooked noodles off-heat or into cooled broth, then fold in the hot noodles gently. Avoid boiling the mayo directly in the pot.
Can I make this ahead?
Best eaten fresh. Store cooked noodles and broth separately; reheat broth and toss with mayo just before serving.
Does this recipe scale up for meal prep?
Yes, prepare broth and noodles in batches, but mix mayo and egg individually per serving to avoid curdling or overcooking.