Heat milk (or soy milk), sugar, and matcha to dissolve. Take care not to boil - just make sure it dissolves completely.
Beat the egg whites in a bowl. Add the matcha mixture in small batches and mix well. (Try not to whisk).
Strain through a fine colander or a sieve as you pour into the container. Use cocottes or cups. (In a pot, bring some water to a boil to use as a hot bath later.)
Remove any fine foam with a spoon or paper towel. Cover with aluminum foil.
Soak the pudding in a pot of hot water. (The water level should match the height of the pudding mixture.) Cover the pot and steam over extra low heat for 7 to 8 minutes. (I doubled the measurements in the photo.)
After about 7 minutes have passed, shake them a bit. If they jiggle slightly, they're ready. Turn the heat off, and let them cook for five minutes in the residual heat. Chill in the refrigerator and they're ready to serve.
To make the brown sugar syrup, combine ◆ ingredients and microwave for 30 seconds. Take it out, stir, and microwave again for another 30 seconds. Make sure the sugar dissolves completely.
I've posted some other pudding recipes that only use egg whites. Please check them out to use-up any leftover egg whites.
Story Behind this Recipe
When I made matcha pudding with whole eggs, the color didn't turn out too good. On the other hand, when I used egg whites only, the resulting matcha pudding was beautifully green.
The pudding becomes porous if the temperature of the pudding mixture and the hot bath is vastly different. That's why it's important to warm the mixture to a certain extent before soaking it in the hot bath. When it has become too cold, cool down the hot bath slightly and then start simmering. Please serve with some brown sugar syrup - they go really well together.