Can I use regular mayonnaise instead of Japanese mayo?
Yes, regular mayo works, but Japanese mayo has a richer, slightly sweeter flavor and creamier texture. Kewpie is the most common brand and worth seeking out for authentic results.
How much water should I add?
Use enough water to just cover the pasta (about 1 cup). The pasta will absorb it as it cooks. Adjust slightly if your microwave is very powerful.
What wattage microwave do I need?
Standard 1000W microwaves work fine. Cooking time may vary by 1–2 minutes depending on wattage; start checking at 4 minutes.
Can I make this ahead?
This dish is best eaten fresh. Leftovers can be refrigerated for 1 day and reheated gently with a splash of water, though the texture will soften.
Is this vegetarian?
No, this recipe contains canned tuna. Omit tuna and add cooked vegetables or tofu for a vegetarian version.