The main ingredients of macarons are egg white, icing or granulated sugar, almond flour or ground almonds and food colorings. A perfect macaron is soft on the inside and crispy and chewy on the outside. The most important technique to achieve this is macaronizing: folding the beaten egg whites through the almond mixture. The nice shine on the macarons is created by finding the right balance between the oiliness of the almond and the lightness of the egg white.
The shelf life of macarons is increased by keeping them cool. The shelf life can be increased when the discs and the filling are stored separately. Freezing is also an option to extend the shelf life but can come at the expense of crispiness.