Wash the pumpkin thoroughly, then remove the seeds and skin.
Cut the pumpkin into small pieces and steam for 20 minutes until soft.
Mash the steamed pumpkin until smooth.
In a bowl, mix the mashed pumpkin with heavy cream, sugar, and milk.
Soak gelatin in cold water, then melt it using a double boiler.
Quickly add the melted gelatin to the pumpkin mixture and stir well.
Pour the mixture into mousse molds and refrigerate for at least 2 hours until set.