If using medium sized eggs, use 90 g of cake flour.
Sift the cake flour. Divide the eggs into whites and yolks and put into separate bowls. Put the matcha in a bowl. Preheat the oven to 340°F/170°C.
Add half the granulated sugar to the egg whites little by little while whipping to make a stiff meringue. Chill the meringue in the refrigerator.
Add the rest of the sugar to the bowl with the egg yolks. Whisk well until the yolks turn white and thick. Add milk and oil.
Sift the flour you sifted in Step 1 again into the bowl with the yolks, and mix well so that there are no lumps.
Fold in 1/2 of the meringue to the batter. Add the rest of the meringue and mix together.
Transfer the batter to the bowl that held the meringue, and mix the batter using a cut-and-fold motion, to leave as much of the air in the meringue as possible.
Add the milk and green tea liqueur to the bowl with the matcha and mix to dissolve (if you do this too early, it clumps up and becomes unusable).
Put 2 ladles full of the batter to the bowl with the matcha, and mix well.
Put 1/3 of the milk batter from Step 6 into the cake mold. Drizzle in 1/2 of the matcha batter evenly. Repeat once more, ending with a layer of the milk batter.
Drizzle in any remaining matcha batter. Marble the batter in the mold by dipping the spatula straight into the mold rather than stirring it around.
Cut into the batter with a spatula 6-7 times, leaving a gap between each cut. (It will become marbled inside.)
Tap the mold on a work surface while holding the middle of the mold. Put into the oven and set the time for 30 minutes at 340F/170C.
Bake for 20 minutes at 340F/170C, then make 4 to 5 cuts in the surface with a serrated bread knife. (This step is optional).
Turn the temperature down to 320F/160 C and bake for another 10 minutes (you can leave the temperature at 340F/170C if you like). If a skewer inserted into the cake comes out clean, it's done.
Take the cake out and invert it on top of a mug or cup, and wait until it has cooled down. (If you try to take it out while it's still hot, it will fall apart.)
When the cake has cooled down, cut around it with a cake knife to separate it from the mold. Separate the cake from the center part with a bamboo skewer.
Invert onto a plate, and it's done. Serve with whipped cream.
Story Behind this Recipe
I wanted to make a matcha marbled chiffon cake... it was surprisingly easy.
Dissolve the matcha tea powder in the liqueur and milk just before you add it to the milk batter. If you do it at the start of the process, it will clump up and become unusable. If it's still hard to mix, add 1 teaspoon of milk and adjust.