Preheat your oven to 300°F (150°C). Line a baking sheet with parchment paper.
In a mixing bowl, sift together almond flour, powdered sugar, and matcha powder.
In another bowl, beat egg whites until frothy, then gradually add granulated sugar and beat until stiff peaks form.
Gently fold the dry ingredients into the egg whites until well combined.
Transfer the batter to a piping bag and pipe small circles onto the prepared baking sheet.
Tap the baking sheet on the counter to release air bubbles. Let the macarons sit for 30 minutes to form a skin.
Bake for 15 minutes. Let cool completely before removing from the parchment paper.
For the filling, beat butter until creamy, then gradually add powdered sugar and matcha powder. Mix until smooth.
Pipe the filling onto half of the macaron shells and sandwich with the remaining shells.