Separate egg whites from yolks, weigh 70 g egg whites and put them in a large mixing bowl.
Add lemon juice to egg whites and set aside for now.
Puree raspberries or strawberries and pass them through a sieve. Weigh 150 g of fruit puree and put it in a saucepan with a thick bottom.
Add 280 g sugar, water and agar agar to the fruit puree in the saucepan and mix until homogeneous.
Place the saucepan with the fruit mixture on the stove and bring to a boil over medium heat, stirring.
Once the fruit mixture boils, turn the heat down to low and simmer the berry syrup for 4 minutes, stirring occasionally.
Beat parallel egg whites with lemon juice until foamy, then add 70 g sugar in batches and beat until stiff.
Immediately after boiling, add the hot berry syrup to the beaten egg whites in a thin stream, without stopping to beat it further.
After stirring the berry syrup into the beaten egg whites, continue beating it for about 2 minutes until it becomes stiff fruit whites.
Fill the berry zephyr mixture quickly (The mixture sets very quickly!) into a piping bag with a star-shaped nozzle, pipe rosettes (two layers in my case) onto a sheet of baking paper and let them dry at room temperature for about 1 hour.
Take two rosettes at a time and stick them together with the bottom side. Dust the berry zephyr with powdered sugar, shaking off any excess powdered sugar.