Line the bottom of a 8" by 4" loaf pan with parchment paper.
In a bowl, whisk together the egg, oil, sugar, matcha, vanilla, and salt.
With a spatula, fold the flour into the egg mixture. Be careful not to overmix. Set aside.
Make cheesecake filling:
In a stand mixer bowl fitted with a paddle attachment, beat together cream cheese, sugar, vanilla and egg yolk until smooth and creamy on low speed.
Assemble:
Transfer the matcha batter into the bottom of the lined loaf pan. Spread the layer evenly with a spatula. Reserve 2 tablespoons of matcha batter for the top.
Add the cheesecake filling on top of the matcha batter.
Scrape the remaining 2 tablespoon of matcha batter over top of the cheesecake filling.
Run a knife through the batter to create a swirl through the cheesecake and brownie mixture.
Tap the loaf pan once or twice to release any trapped air bubbles.
Bake at 350°F/177°C for 25-28 mins, until set in the middle, or a toothpick inserted comes out clean. Remove from the oven and cool on a cooling rack.
Let completely cool before slicing into squares. Dust with additional matcha powder if you wish.
Place into a container for up to 1 day at room temperature, or in the refrigerator for up to 3 days. The tops will be appear a little moist if covered, but this is OK. If you prefer, you can dust with matcha before serving.
Notes
Recipe can be doubled to fit into a 8" x 8" baking pan. Bake for 28-30 minutes, until set.