Whisk the egg white in a bowl until stiff peaks form when the whisk is removed. Slowly whisk in the lemon juice, peppermint and icing sugar to a stiff paste.
Tip the peppermint mixture onto a work surface dusted liberally with icing sugar and roll out thinly.
Use a 5cm/2in cutter to cut out circles and place them onto a baking tray. Chill in the fridge for 1-2 hours, or until the mixture has set.
Meanwhile, melt the chocolate in a bowl set over a pan of simmering water. (Do not let the base of the bowl touch the water.)
Dip each peppermint cream into the melted chocolate and set aside on a baking tray. Chill the peppermint creams until set.