Sift together powdered sugar and almond flour twice to ensure a fine mixture. In a large bowl, whip egg whites until foamy, gradually adding granulated sugar. Whisk until stiff peaks form, about 5-7 minutes.

Gently incorporate green gel food coloring into the meringue until mixed. Fold in the sifted mixture carefully to avoid deflating the meringue.

Transfer the macaron batter into a piping bag and pipe tree shapes or circles about 1.5 inches wide on lined baking sheets. Rest for 30-60 minutes until a skin forms.

Preheat oven to 300°F (150°C) and bake for 14-16 minutes, rotating trays halfway through. Remove when they have formed a ‘foot’ and cool on sheets.

In a bowl, beat the softened butter until light and fluffy. Gradually mix in powdered sugar, heavy cream, and vanilla extract, then fold in crumbled snack cakes.

Pair macaron shells, pipe filling on one shell, sandwich with another, and for an extra festive touch, drizzle with melted white chocolate and sprinkle decorations.

Refrigerate assembled macarons in an airtight container for at least 24 hours to enhance flavors before serving.