Halve the pumpkin, remove the seeds, peel and cut into cubes. Then cook in the soy milk with the sugar and cinnamon for about 20 minutes until soft. Make sure that the milk does not foam over.
When the pumpkin is soft, remove the cinnamon stick and purée everything.
Put back on the heat and boil down the mixture, stirring constantly (approx.1h).
When the mixture thickens, add the vanilla extract and pour into sterilized jars. Put the lids on and turn upside down. Leave to cool.