Sift powdered sugar and almond flour together in a large bowl twice to ensure a smooth mixture.

In a separate bowl, beat room temperature egg whites until frothy. Gradually add cream of tartar and then granulated sugar while continuing to beat until stiff peaks form.

Fold in green gel food coloring gently into the meringue.

Carefully fold the sifted almond flour mixture into the meringue until a flowing batter forms.

Pipe tree shapes or circles of about 1.5 inches in diameter on lined baking sheets.

Let piped macarons rest at room temperature for 30-60 minutes.

Preheat the oven to 300°F (150°C) and bake macarons for 14-16 minutes, rotating trays halfway.

Allow macarons to cool on baking sheets for about 10 minutes before transferring to a wire rack.

Beat softened butter in a bowl until fluffy, then gradually add powdered sugar, vanilla extract, heavy cream, and salt. Fold in crumbled snack cakes.

Pair similar-sized macarons and pipe filling between them.