Whisk the egg whites until fluffy, then gradually whisk in the icing sugar. Place over a pan of hot water and whisk until the mixture thickens and holds its shape. Fold in the hazelnuts.

Place in a piping bag with a large star nozzle. Pipe into 2 heart shapes onto 2 baking trays lined with silicone paper. Bake at 150 °C / 300 °F / Gas 2 for 1 - 1 1/2 hours until firm. Cool.

Gradually blend the melted chocolate into cream, add the rum and beat until it forms soft peaks. Use to fill and decorate the meringues. Decorate the meringues with chocolate hearts and leaves and serve.