Mash up the tofu in a bowl and make it smooth. Add the egg and salt, then mix some more.
Transfer everything from the bowl into a container that's about the size of a rice bowl. Cover it with aluminum foil. (Poke a few holes in the foil with a fork.)
Microwave for 5 minutes! (Please adjust the heating time to your microwave.)
Put the water, dashi soy sauce, and green onions in a small pan and bring to a boil. Add the katakuriko dissolved in water. When the mixture becomes thick, pour it over the egg-tofu and enjoy!
Story Behind this Recipe
My son loves chawanmushi (steamed savory custard). When I was trying to think of diet-friendly menus for my husband, I remembered that I used to make chawanmushi a lot in the microwave! That was what inspired me to put this recipe together. The key is to make a thick ankake sauce.