Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.

In a large mixing bowl, cream together the butter, granulated sugar, and brown sugar until light and fluffy.

Add in the egg and mix until just combined.

In a separate bowl, whisk together flour, matcha powder, baking powder, and salt. Gradually add to the wet mixture.

Scoop cookie dough onto baking sheets, spacing them 2 inches apart, and flatten lightly.

Bake for 10-12 minutes, until edges are golden brown and centers are slightly set.

Cool cookies on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.

Assemble sandwiches by placing a scoop of matcha ice cream between two cookies.

Wrap in plastic wrap and freeze for at least 1 hour before serving.

Serve and enjoy!