Preheat the oven to 350 degrees.

In a large bowl, beat the butter and sugar together until light and fluffy, about 2-3 minutes. Add in the eggs and vanilla and beat until creamy.

Add in the flour, salt, baking powder, baking soda and matcha powder and mix. The dough will be stiff, but be patient as it will come together.

Use a 1 ½” Tbsp cookie scoop to achieve uniform cookie sizes and scoop the dough onto a baking sheet, spacing the cookies about 2-3” apart. 

Place in the oven and bake for 10-11 minutes, just until the edges start to turn golden. Remove and let the cookies cool on the pan for about 3 minutes before transferring to a cooling rack to come to room temperature.

To make the filling, place the butter in a medium sized bowl and beat for 1-2 minutes until the butter lightens in color. Add in the vanilla and powdered sugar and beat until creamy. 

Place the filling into a piping bag with a circle tip (#12 shown) and pipe the filling onto one side of the cookie in a circular motion. Top with another cookie and gently press the cookies together so the frosting adheres to both sides and creates a sandwich. Repeat until all the cookies are paired into sandwiches.

Store any leftovers in an airtight container for up to 4 days.