Preheat your oven to 350°F and line or spray a 9 x 9-inch square pan.
In a large mixing bowl, cream together butter, oil, and sugar with a hand mixer on high until the mixture is smooth.
½ cup unsalted butter, softened, 1 ¼ cup granulated sugar, 2 tablespoons oil
Add vanilla extract and eggs and mix again until combined.
2 teaspoons vanilla extract, 2 large eggs
Next, add your flour and salt and mix again until well-combined and no clumps remain.
½ cup all-purpose flour, ¼ teaspoon salt
Use a measuring cup to scoop out about 1/2 cup of your batter and place it in a separate mixing bowl. Add your matcha powder and stir until smooth.
2 tablespoons matcha powder
Add the cocoa powder and chocolate chips to the leftover batter to create a smooth, fudgy brownie batter.
½ cup cocoa powder, ½ cup chocolate chips
Add the chocolate brownie batter to the prepped pan first and use a spatula to smooth it out. Then, add the matcha batter on top sporadically, and use a spoon, knife, or spatula to swirl the two batter together, creating a marbling effect.
Bake for 30 minutes if you like your brownies gooey. Leave them slightly underbaked but allow them to cool and solidify before cutting them. If you are more of an edge brownie person, bake for 35 minutes or until a toothpick comes out clean.