Preheat the oven to 325F and line a 9" x 9" brownie pan with parchment paper, leaving a few inches hang-over on two sides to act as handles for pulling out the finished bars.
Begin by making the shortbread crust. In the body of a food processor, combine the flour, sugar, confectioner's sugar, salt, and lemon zest and pulse a few times to combine. Add the butter and pulse until a crumbly dough forms.* Use your hands to press the dough into the prepared pan and bake for 30-35 minutes, until just lightly golden. Set aside.*
In a small bowl, whisk together the eggs, lemon juice, sugar, and lemon zest. Set aside.
In a medium bowl, whisk together the flour, cornstarch, baking powder, salt, and Matcha. Add the egg mixture and whisk to combine. Pour over finished shortbread crust and bake for 25-30 minutes, until the center is set and no longer wobbles when you shake the pan.
Place the pan on a wire rack on the counter and let cool to room temperature before transferring to the refrigerator to finish setting, about four hours. Once firm, remove the bars from the pan and cut into 9 or 12 squares before dusting with powdered sugar. Serve immediately. These will remain fresh for up to 3 days in an airtight container on the counter.
Note: If you don’t have a food processor, whisk the shortbread ingredients (excluding the butter) in a large bowl. Add the cubes of butter and use a pastry knife or two regular knives to cut it in, forming a crumbly dough. Follow the rest of the steps as listed.
Note: You can begin making the filling while the crust is in the oven - pouring the filling onto the hot crust is not a problem and will streamline making these bars.
Click below to purchase the Culinary Grade Matcha used in this recipe: