In a small pan, bring the cream to just below the boil. Remove the pan from the heat, add the tea bag, leave to cool, cover and chill for approx. 1 hr. Carefully squeeze out the tea bag and remove.
Place the chocolate and 4 tbsp of peppermint cream in a thin-sided bowl and suspend over a gently simmering bain-marie, ensuring that the bowl does not touch the water. Melt the chocolate and stir until smooth. Remove the bowl, allow to cool slightly. Using a rubber spatula, carefully fold in the whipped cream. Transfer the mousse to a piping bag with a smooth nozzle (approx. 16 mm in diameter), divide between the glasses, cover and chill for approx. 3 hrs. Add the peppermint to the remainder of the peppermint cream, whip until stiff. Transfer the whipped cream to a piping bag with a serrated nozzle (approx. 12 mm in diameter) and pipe onto the mousse. Top with the chocolate shavings and mint.