Preheat the oven at 100 degrees Celsius.
Pour the sugar in a bowl, add the egg whites and mix with an electrical mixer until you have a white firm foam.
Add the citron juice and mix gently.
Make small circles of the foam on a baking paper.
Place in the middle of the oven for approx. 1 hour.
Take the meringue out and let it cool down before serving them.