Start by sifting powdered sugar and almond flour together in a bowl. Repeat sifting twice to ensure a smooth mixture.

In a clean bowl, beat egg whites until foamy, adding cream of tartar and granulated sugar gradually until stiff peaks form (about 5-7 minutes).

Add green gel food coloring to egg whites and fold in sifted almond flour mixture gently until the batter flows smoothly.

Transfer the batter into a piping bag and pipe tree shapes on parchment-lined baking sheets.

Allow pipes shells to rest for 30-60 minutes until a skin forms on the surface.

Preheat oven to 300°F (150°C) and bake macaron shells for 14-16 minutes, rotating halfway through.

Beat softened butter until fluffy, then gradually add powdered sugar, vanilla, heavy cream, salt, and crumbled snack cakes to create the filling.

Once cooled, pipe filling onto one macaron shell and sandwich with another. Drizzle with melted white chocolate and sprinkle decorations.

Refrigerate assembled macarons for at least 24 hours to mature the flavors before serving.