To poach the raspberries, place the cordial in a medium-sized saucepan with the cinnamon stick and vanilla extract and bring to the boil. Turn down the heat and simmer for 5-10 minutes until reduced by half and slightly thickened. Allow the cordial mixture to cool, then place the raspberries in a bowl and pour the cordial mixture over them through a sieve, discarding the cinnamon stick. Stir to combine and set aside.
Whip the cream in a bowl until it forms soft peaks. Place the custard in a bowl, whisk in the mascarpone cheese until completely smooth and then fold in the grated white chocolate and the whipped cream until evenly mixed.
Spoon the poached raspberries, reserving the liquid, into the base of six glass bowls or martini glasses, then arrange three Cantuccini biscuits in each glass, breaking them up as necessary to t. Pour the raspberry liquid over and then spoon the white chocolate mixture on top to cover completely. Chill for 1 hour until set.
Garnish each tiramisu with grated white chocolate and the extra raspberries and sprigs of mint.