For the pumpkin jam with cinnamon, stir pumpkin flesh, spice and juice of one lemon with jelling sugar and let stand at least 2 hours, better one night.
Next, heat until it bubbles and simmer as long as indicated in the jam sugar instructions.
Using a blender, puree everything together and let it bubble again briefly. Pour the pumpkin jam with cinnamon into twist-off jars, seal, turn upside down briefly and you’re done.