Put all the dry ingredients (except for the matcha powder) in a bowl, add the lemon zest and mix well. Squeeze the lemon, mix the juice with the milk and stir well. The milk should thicken a little. Pour the milk and oil over the dry ingredients and mix to a smooth batter. Pour about a third of the batter into a separate bowl, add the matcha powder and stir.
Fill half of the light dough into a loaf pan, then pour the matcha dough over it and put the rest of the light dough on top. Marble vigorously with a wooden spoon or a fork. Bake in the preheated oven at 170°C circulating air for about 50 min. Don't forget to test with a stick! Then let the cake cool down in the mold before getting it out.
Melt the chocolate in a water bath and mix in the matcha powder. Decorate the cake with the glaze and let it cool down again.