Sift the powdered sugar and almond flour together into a bowl twice to eliminate lumps.

Beat the egg whites in a clean mixing bowl until foamy, then gradually add cream of tartar and granulated sugar until stiff peaks form.

Fold in the green gel food coloring into the meringue gently.

Gradually fold the sifted almond flour and powdered sugar mixture into the meringue until a smooth batter forms.

Pipe the macaron batter onto lined baking sheets in desired shapes.

Let piped macarons rest at room temperature for 30-60 minutes until a dry skin forms.

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

Cool the baked macarons completely on the baking sheets for about 10 minutes.

Beat the butter until fluffy, then gradually mix in the powdered sugar, vanilla extract, heavy cream, and salt.

Fold in the crumbled snack cakes into the filling mixture.

Pipe filling onto one macaron shell and sandwich with another shell.

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