In a food processor, crush the chocolate graham crackers and transfer to a large bowl. Add the cream cheese and mix by hand until the mixture is homogenized.
Spread the mixture evenly in a 20 cm/8 inch diameter detached cake pan lined with parchment paper and set aside.
For the filling:
Soak the gelatin in a bowl of water and ice. Once soft, strain, add 100 ml/½ cup of water, melt in the microwave for a few seconds and set aside.
Place the egg whites in a mixer bowl and beat with the whisk attachment on medium to high speed until a meringue is created.
Add the caster sugar in batches and blend until the mixture is homogenized. Add the gelatin mixture and mix well.
Spread half of the mixture evenly over the base.
Add the cocoa to the rest of the mixture, stir gently with a spatula, and pour over the white mixture in the pan. With a spoon, gently mix the white mixture with the brown mixture.
Transfer to the refrigerator for 4 hours and, as soon as the zebra cake has cooled well, unmold, and serve.
Notes
Make sure the water for the gelatin is not too warm so as not to burn the gelatin!
