Prep: Line a baking sheet with parchment paper and set aside.
Mix dry ingredients: In a large mixing bowl, stir together flour, sugar, matcha powder, baking powder, and salt.
Cut butter into flour: Add the cubed butter and toss to coat in the flour mixture. Break the butter pieces into small pea-sized pieces with a dough blender or by pressing them in between your fingers.
Mix wet ingredients: In a separate medium bowl, whisk together heavy cream, the egg, and vanilla extract.
Add wet mixture - Make a well in the middle of the flour mixture. Pour the wet mixture into the well and mix until it forms a soft and crumbly dough. Some dry patches are fine but the dough should hold together when pressed.
Press dough together: Turn the dough out onto a lightly floured surface. With floured hands, press the dough together into a flattened disc shape that's about 1" thick.
Cut dough: Use a bench scraper or a knife to cut the dough into 8 wedges. Transfer them to your lined baking sheet, leaving about 2" in between each one.
Chill and preheat: Place the entire baking sheet into the fridge to chill while you preheat the oven to 400°F.
Brush scones: Right before baking, brush the tops of each scone with a thin layer of heavy cream. Sprinkle coarse sugar on top of the cream.
Bake: Bake scones for 18-20 minutes or until the tops are lightly golden brown. Let them cool on the baking sheet until firm enough to transfer to a wire rack.