01 - Preheat oven to 350°F (175°C). Line an 8x8-inch baking pan with parchment paper, allowing an overhang for easy removal.
02 - Combine unsalted butter and chocolate chips in a heatproof bowl. Melt in 30-second intervals in the microwave or over a bain-marie, stirring until smooth. Allow to cool slightly.
03 - Whisk granulated sugar, eggs, and vanilla extract into the cooled chocolate mixture until evenly blended.
04 - Fold in all-purpose flour and salt gently until just combined. Set the brownie batter aside.
05 - In a separate bowl, beat cream cheese and granulated sugar together until smooth and creamy.
06 - Mix in the egg, all-purpose flour, matcha powder, and vanilla extract. Continue beating until fully combined.
07 - Spread two-thirds of the brownie batter evenly in the prepared pan. Spoon the matcha cheesecake mixture in dollops over the brownie layer, then add the remaining brownie batter.
08 - Use a skewer or knife to gently swirl both mixtures, forming a marbled appearance.
09 - Bake for 35 minutes, until the edges are set and the center has a slight jiggle.
10 - Allow to cool completely in the pan. Lift out using the parchment overhang and slice into squares.