1-Preheat the oven: Preheat the oven to 300 degrees Fahrenheit with the rack in the lower third.

2-Sift dry ingredients: Sift together the almond flour, powdered sugar, and matcha powder twice.

3-Whisk egg whites and sugar: In a clean bowl of a stand mixer with a whisk attachment, whisk the egg whites and granulated sugar gently. Beat at medium speed for 2 minutes, then medium-high for 2 minutes more, and finally high speed for another 2 minutes until the meringue is very stiff and glossy.

4-Fold dry ingredients: Fold the sifted dry ingredients into the meringue using a rubber spatula with a circular motion, about 40-43 strokes, until the batter reaches a molten lava consistency.

5-Pipe batter: Transfer the batter to a piping bag with a ⅜-inch round tip. Line baking sheets with parchment paper. Pipe ¾-inch rounds spaced 1 to 1½ inches apart. Tap the sheets to release air bubbles and let them rest for 20-30 minutes until dry to the touch.

6-Bake macarons: Bake one sheet at a time for 13-16 minutes until the macarons have risen and the tops no longer jiggle. Cool completely before filling.

7-Prepare buttercream: For the buttercream, cream the butter in a stand mixer with a paddle attachment on medium speed. Add the powdered sugar, ground freeze-dried mangoes, vanilla extract, and salt on low speed until combined. Add the heavy cream 1 tablespoon at a time until the mixture is soft but pipeable.

8-Finish macarons: Match the macaron shells by size. Pipe the buttercream onto half of the shells and sandwich with the matched shells. Refrigerate in an airtight container for 1-3 days to ripen. Serve at room temperature.