Clean seeds and peel pumpkin slices, cut in to cubes, put in a pot, sprinkle sugar evenly over pumpkin, close the lid and let it wait over night

In the morning you will see that pumpkin slices released their juice.

Start the pot boil with lid close, about 1 hour and so. After that open lid and continue boiling about 15 more minutes . You will see it's juice get thickened and caramelized. If not, continue boiling with low medium heat. Turn it off .

Wait until it gets cold, serve with chopped walnut.