For the Coca-Cola syrup, whisk all of the ingredients together in a small saucepan over medium heat. Simmer, while whisking regularly, for 8-10 minutes until sticky and syrupy. Store at room temperature.
For the crust, place the biscuits in a food processor and process until fine. Melt the butter and white chocolate over a double boiler, over very low heat, until smooth. Combine with the fine biscuits and press into 22cm pie dish or tin. Refrigerate for 20 minutes.
For the filling, combine the pudding powder, Coca-Cola and Ideal milk. Whisk for 2 minutes and refrigerate for 10 minutes. Whip the cream until stiff. Fold the cream through the pudding mixture and spoon the mixture onto the biscuit base. Refrigerate for 1 hour.
To serve, whip the cream until soft peaks form. Add the sugar and whisk until stiff. Lightly ripple half of the Coca-Cola syrup through the cream and spoon on to the tart. Drizzle the remaining syrup on top and garnish with the cherries.