Preheat the oven to 325°F. Line an 8 by 8 inch baking pan with parchment paper.
The Batter
In a medium-sized bowl, whisk the 180 g all-purpose flour, 10 g matcha powder, and 1/4 tsp salt together until well-combined. Set aside.
Using a stand mixer or hand mixer fitted with the paddle attachment, beat the 170 g unsalted butter (grated), 70 g sugar, and 1/2 tsp vanilla extract together until light and fluffy.
Add the dry ingredients from step two, and mix on low speed until just combined.
Fold in the chopped 90 g dark chocolate with a baking spatula.Chef's Tip : Make sure to save some of the chopped chocolate on the side to press into the tops of the bars right before baking for a prettier look.
The Baking
Press the dough into the prepared baking pan into an even layer. Press the reserved chocolate into the top.
Bake for 25-30 minutes. You should see a nice golden coloration start on the sides.
Let cool completely on rack, and cut into squares of your desired size. I cut them in 16 pieces (4 by 4).
The Serving
Serve and enjoy your Matcha Chocolate Bars [抹茶チョコバー]!