Bailey's mousse

Instructions

1. Reserve 1 tbsp caster sugar. Place the remaining sugar and water in a small heavy based saucepan. Heat gently until the sugar dissolves, then boil rapidly for about 1 minute until the mixture is syrupy, but not caramelised.
2. Whisk the egg whites in a grease-free bowl until stiff, then slowly add the sugar syrup, beating well to thoroughly combine.
3. Put the 3 egg yolks, remaining sugar and liqueur in a large heatproof bowl. Position the bowl over a saucepan of gently simmering water and whisk until thick and frothy. This will take at least 5 minutes. Whisk in the egg white mixture. Share between 6 glasses. Chill in the fridge.
4. Whisk the whipping cream until it holds its shape. Use to top the desserts, then serve at once, sprinkled with the cocoa powder (if using).