Preheat oven to 160°C.
Bring milk and cinnamon to a boil in a 2L container.
Add sago and cover dish. Leave to soak for 90 minutes or over night if possible.
Whisk the milk mixture and bring to a boil whilst whisking again for 2 minutes.
Allow the mixture to cool slightly.
In a separate bowl, whisk egg yolks and vanilla together and whisk it quickly into cooled down mixture.
Pour into a buttered dish.
Half fill a larger dish, and place the sago dish in to create a bain marie.
After baking, spread apricot jam gently over the pudding.