For food safety, you may use pasteurized eggs or substitute the raw egg whites with an equal volume of whipped cream for a lighter, safer version.
If you prefer a stronger coffee flavor, add a tablespoon of coffee liqueur to the espresso mixture.
This dessert can be made up to 2 days in advance. Store covered in the refrigerator.
To serve, you can dust the top with additional cocoa powder or shaved chocolate just before serving.