Remove the skin and seeds from the sweet pumpkin, then cut it into small pieces.
In a pot, combine the sweet pumpkin, milk, and sugar, and bring to a boil.
Simmer over low heat, stirring occasionally, until the pumpkin softens.
Blend the mixture until smooth using a blender.
Pour it back into the pot and simmer over medium-low heat until it thickens to a jam-like consistency.
Transfer the finished jam into a sterilized jar and let it cool.