Begin by sifting powdered sugar and almond flour together twice in a large bowl to ensure a smooth, lump-free mixture. Set aside.

In a separate mixing bowl, beat room-temperature egg whites on medium speed until foamy, about 2 minutes. Gradually add cream of tartar and sprinkle in granulated sugar, beating until stiff peaks form, about 5-7 minutes.

Once your egg white mixture reaches stiff peaks, carefully fold in a few drops of green gel food coloring using a spatula until an even color is achieved.

Gently fold the sifted almond flour mixture into the egg whites using a spatula until the batter flows like lava and has a smooth appearance.

Prepare a piping bag fitted with a round tip and pipe the batter onto parchment-lined baking sheets in desired shapes. Allow to rest for 30-60 minutes until a dry skin forms.

Preheat the oven to 300°F (150°C). Bake the macarons for 14-16 minutes, rotating halfway through for even cooking, then cool completely.

Beat softened butter until fluffy, gradually mix in powdered sugar, then heavy cream, salt, and crumbled snack cakes until fully combined for the filling.

Once cooled, pipe a generous layer of filling onto the flat side of one macaron shell and sandwich with another shell.

For an optional decoration, melt white chocolate and drizzle over macarons, and sprinkle with edible decorations.

Store assembled macarons in an airtight container and refrigerate for at least 24 hours to allow flavors to meld.