Start by sifting together the powdered sugar and almond flour twice to ensure a smooth macaron shell.

In a separate bowl, whip the egg whites using a stand mixer on medium speed until foamy. Gradually add granulated sugar while mixing, and continue beating until stiff peaks form, which should take about 5-7 minutes.

Gently fold in the green gel food coloring to the whipped egg whites until uniformly colored.

Carefully incorporate the sifted almond flour mixture into the egg whites, using a spatula to fold until you achieve a batter that flows like lava.

Transfer the vibrant batter into a piping bag fitted with a round tip. Pipe tree shapes on lined baking sheets, leaving space between each.

Let the piped macarons rest for 30-60 minutes until a skin forms on the surface.

Preheat your oven to 300°F (150°C) and bake each tray of macarons for 14-16 minutes, ensuring to rotate halfway through.

Remove the macarons from the oven and let them cool on the baking sheets for 5 minutes before transferring them to a wire rack.

In a clean bowl, beat softened butter until fluffy. Gradually mix in the powdered sugar, vanilla extract, and heavy cream.

Pipe a generous dollop of filling onto the flat side of half of the macaron shells and sandwich with the remaining shells.

For added flair, drizzle melted white chocolate on top and sprinkle with festive decorations.

Refrigerate the assembled macarons for 24 hours before serving for the best flavor.