Mix the yogurt, lemon juice and about 1/3 of the powdered sugar until creamy. Chill this mixture for about 1 hour.
Then beat the egg whites, the rest of the powdered sugar and the salt until they are stiff. Fold the egg whites into the lemon mixture until everything is evenly mixed.
Freeze in the ice cream maker for about 35 minutes (until the consistency is good).
The ice cream can then be garnished with lemon balm or lemon wedges.
For a change, you can also use other fruit juices.