Wash the sweet pumpkin thoroughly, remove the skin and seeds, and cut it into small pieces.
Place the sweet pumpkin and water in a pot and boil until fully cooked.
Mash the boiled sweet pumpkin finely.
Add sugar and lemon juice to the mashed pumpkin and simmer over low heat, stirring continuously.
When it becomes thick, turn off the heat and let it cool.
Store in a sterilized jar.