Bring the cream, milk and broken cinnamon sticks to the boil. Cream together the sugar and egg yolks. Pour the boiling cream mixture onto the creamed yolks, stirring from time to time until cooled. Pour through a sieve and then churn in the ice-cream machine for 15–20 minutes until very thick. Freeze. The ice-cream will be nice and rich and packed with cinnamon flavour.