In a large bowl, combine eggs, Dashi, salt and Mirin. Mix very well, and strain.

Pour the egg mixture into 4 small cups. Place the cups in a steamer covered with a lid, wrapped with cloth, and steam for 12-13 minutes at medium low heat.

Meanwhile, in a small pot, heat all the ingredients for the sauce until boiling. Cool.

When the egg mixture is solidified, remove from the steamer. Poke a hole to check the doneness. If the clear liquid seeps through the hole, it's done.

Refrigerate until cold for a couple of hours. Pour the sauce over before serving.