For the cinnamon sauce in a small saucepan over medium heat combine the brown sugar, the flour and 180ml hot water, cook until uniform, add the butter and 3/4tsp cinnamon powder, cook until thickened and smooth. Cool and store in an airtight container until ready to use.
For the ice cream in a blender combine the cream cheese, sour cream, thin pouring cream, sugar, 1/2 cinnamon powder and the vanilla bean powder, whizz away until really smooth and creamy. Chill in the fridge overnight.
Freeze in your ice cream maker according to the manufacturer's instructions adding the crushed chocolate cookies at the last couple of minutes of churning. Spoon into an airtight container alternating layers of ice cream and the cinnamon sauce (6-8tsp), store in the fridge for at least 5 hours until set.