Whisk the egg whites in a bowl until stiff, then add the rest of the ingredients (except the Matcha), one at a time, stirring with a wooden spoon so as not to lose the soft peaks.
Pour 2/3 of the mixture into a baking tin.
Add the Matcha to the remaining dough, mixing well, then spread it over the previous mixture.
Bake the plumcake for 30-45 minutes until it is well cooked in the centre.
Take it out of the oven and let it cool completely before cutting it into slices and serving.
