For the meringue:

1. Mix the egg whites and sugar with a whisk.

2. Place the sugar and egg white mixture in a double boiler and heat gently while constantly mixing. When the sugar is dissolved in the egg whites, transfer everything to the mixer.

3. At medium speed, whip the meringue with the whisk until the mixer bowl has cooled or the meringue forms firm peaks.

The meringue is shiny and ready to use. Set aside.

4. In the blender, reduce the blackberries to a smooth puree. Then pass them through a fine-mesh sieve to remove the seeds.

5. Pour in the yogurt and add the sugar. Mix well with 200 g of meringue.

6. Transfer the mixture obtained into glasses to one-third of the height.

7. Arrange a few blackberries and layer the mixture again.

8. Place in the freezer for 1 hour before serving.