In a large bowl, whisk together the granulated sugar, brown sugar, melted cooled butter, egg, and vanilla until smooth.
Sift in the flour, baking soda, salt, and matcha powder. Fold just until combined, then fold in the white chocolate.
Divide the dough into 6 large portions and shape them into tall, cylindrical mounds. Arrange them on the lined baking sheet, leaving 2 inches between each one. Chill for at least 1 hour, or until rock solid.
Preheat the oven at 400°F. Bake straight from cold for about 14 minutes, or until the edges are set and the centers no longer look wet.
Let the cookies cool on the baking sheet for 10 to 15 minutes before moving them to a wire rack to cool completely. Sprinkle with sea salt, if using. Serve and enjoy!