Cut the cleaned pumpkin flesh into cubes approx. 1.5 cm by 1.5 cm. Bring the vinegar, cider, salt and sugar to the boil. Add pumpkin cubes and cook for 5 minutes. Remove the pumpkin cubes with a slotted spoon and fill them into six large, clean screw-top jars that have been rinsed with hot water. Put a third of the cinnamon stick in each glass.
Bring the stock with the remaining spices to the boil and pour into the glasses while hot. Leave a little space to the edge. Now fill up to the brim with calvados.
Close the jars immediately and let them cool upside down. This creates a vacuum and the pumpkin can be kept longer (at least 2 years).
Before the first consumption, the pumpkin should steep for at least a week.