Preheat your oven to 150°C (300°F). Prepare a baking sheet lined with parchment paper.

In a large bowl, sift together almond flour and powdered sugar until well combined.

In another bowl, whip the aged egg whites until stiff peaks form. Gradually add granulated sugar while continuing to whip.

Gently fold the dry ingredients into the meringue until fully incorporated. Add food coloring if desired.

Transfer the batter to a piping bag and pipe small circles onto the prepared baking sheet.

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

Bake the macarons for 12-15 minutes. Allow to cool completely on the baking sheet before removing.

In a mixing bowl, beat softened butter until creamy and smooth.

Gradually add powdered sugar and beat until well combined and fluffy.

Mix in vanilla extract and fruit puree or melted chocolate until fully incorporated.

Pipe the buttercream onto the flat side of one macaron shell and sandwich with another shell.