‘In passing through the Maconnois,’ wrote Tobias Smollett in 1766, ‘I observed a vast quantity of very large pompions [pumpkins] with the contents of which they thicken their soup and ragoûts.’ And so they still do, two centuries later.
Halve the potatoes, or quarter them if large. Peel the pumpkin and remove any seeds and fibres: you should have about 625g/1½lb peeled flesh. Cut it into pieces about the same size as the potatoes.