Break the chocolate and mint bar into pieces. Heat the cream. Melt the chocolate and mint bars in it while stirring. Let the truffle mixture cool down a little and then put it in a cool place overnight
Press the aluminium moulds slightly apart. Cream the truffle mixture with the whisk of the hand mixer. Pour into a piping bag with a large star-shaped spout. Pour the truffle mixture into the moulds and chill for at least 1 hour. Decorate with chocolate hearts. Store in a cool place