- Preheat the oven to 150°C (300 °F) and cover a baking sheet with parchment paper.
- Sift the cornstarch and the cocoa powder and set aside.
- In a large bowl, add salt to the egg whites and beat them with an electric whisk until you get soft peaks. Gradually stir in the sugar until the whites are shiny and stay in the bowl when you turn it over.
- Add the cornstarch and cocoa mixture to the egg whites and continuing to whisk. Add the balsamic vinegar and continue beating until you get a homogeneous mixture.
- Using 2 large spoons, spoon 4 mounds of the mixture about 10 cm (3 1/2 po) in diameter onto the parchment paper lined baking sheet, flattening the tops slightly.
- Bake for 1 hour, or until the balls are firm on the outside and moist inside.
- Allow to cool completely to room temperature for 2 hours. Delicately put on a plate and set aside.
- To prepare the chocolate sauce; Combine the chocolate and cream in a saucepan and warm over low heat. Whisk together until chocolate is melted and cream is incorporated with chocolate then set aside.
- Preparation of the whipped cream and making the Pavlovas: When the meringues are completely cooled, pour all the ingredients of the whipped cream into a bowl and beat with an electric whisk until the cream begins to form firm peaks. Spread out over the Pavlovas and reserve in the refrigerator.
When serving, add the mandarins to the Pavlovas and drizzle the chocolate sauce over them (heat sauce for a few moments in the pan if necessary).