Prep: Preheat the oven to 350°F.
Dry ingredients: In a medium bowl, stir together flour, baking powder, and matcha powder. Set aside.
Separate eggs: Separate the egg whites and egg yolks into two separate large mixing bowls, being careful not to get any of the yolks in the egg whites. Set aside the bowl of yolks.
Beat egg whites: To the bowl of egg whites, add cream of tartar. Use an electric hand mixer to beat the egg whites on medium speed until it resembles cappuccino foam. Sprinkle in 100g of sugar, one spoonful at a time, mixing well in between each addition. Continue beating until it becomes stiff peaks. Set aside.
Egg yolk mixture: To the bowl of egg yolks, add the remaining 50g of sugar, milk, oil, and vanilla extract. Use the same hand mixer to mix until combined.
Sift in flour: Use a fine mesh sieve to sift the flour mixture into the egg yolk mixture. Mix until combined.
Fold meringue into egg yolk mixture: Add ⅓ of the egg white meringue to the egg yolk mixture. Fold together with a spatula until mostly combined. Add the rest of the meringue and fold together until no streaks remain and the batter is fluffy and airy.
Fill pan: Pour the cake batter into a 10" ungreased tube pan, pouring in one spot and letting the batter flow into the rest of the pan to avoid creating air pockets. Lift and drop the pan onto the counter once to release any large air bubbles.
Bake: Bake for 35-40 minutes or until the edges and top of the cake start to lightly brown. After removing the cake from the oven, immediately flip the pan over and let the cake cool completely for at least 2-3 hours upside down, resting on the legs of the pan or a wire rack for airflow underneath.
Release cake: When the cake has cooled, flip it back over and run an offset spatula or skewer around the outer edges of the cake. Pull the inner tube upwards to release the cake. Flip the cake upside down and pull the inner tube out of it.
Slice: With a serrated knife, cut the cake into 6-8 wedges. Turn each slice 90° so that the outer side of the cake is now on the bottom. Cut a slit into the cake lengthwise, without cutting all the way through.