Cut off the top of the pumpkin about two-thirds of the way up. Scoop out the inside. Remove seeds if necessary, then place lid back into position on top of bowl.
Heat oven to 200 degrees. Cut the pumpkin flesh into pieces and put in a roasting tin with cut cloves of garlic and a good glug of oil. Season the pumpkin pieces with the spices, then put it in the oven at 180 degrees for 45 minutes until very tender. Leave to cool.
Tip the pumpkin into a food processor with any juices from the roasting tin and the garlic. Blend together until smooth. Add the lemon juice, tahini paste, and chickpeas to create a thick paste. Season with salt. Before serving, spoon the hummus back into the pumpkin. Serve with pitta chips, breadsticks, and sliced bell peppers for dipping