For the blackberry parfait:
* The parfait should be prepared first since it must be frozen to assemble the dessert.
Put a bowl with the egg whites and sugar in a pot with boiling water. Stir until the sugar crystals have dissolved and the whites feel warm.
Remove from the bain-marie and beat until making a meringue with stiff peaks and the mixture is cold.
Use a hand blender or similar tool to mash the blackberries and strain to remove the seeds.
Whip the cream to a semi-whipped point, meaning it is firm but not Chantilly.
Incorporate the meringue carefully, blackberry pulp, and beat until smooth.
In a loaf pan or oven tray with plastic wrap, spread the blackberry batter, flattening and smoothing the surface.
Cover with plastic wrap and put in the freezer until hard (about 6 hours).
To make the chocolate disks, melt both types of chocolate in a bain-marie, separately.
Then spread it on a baking or plastic sheet, forming a smooth thin layer, and allow to cool.
Right before it hardens, cut into circles with a circular cutter and do not move them until totally hardened.
When serving, put a chocolate disk in the plate, use the same cutter to cut a portion of frozen blackberry parfait, place it over the chocolate, and cover with another chocolate disk, then parfait again, and finish with another disk.