Halve and deseed the pumpkin/squash, leaving the skin on. Drizzle with the extra virgin olive oil, add the halved garlic bulb, thyme sprigs and season well with salt and pepper. Wrap up tightly in aluminium foil and roast until the flesh is very tender - around one hour.
When cooked through, scoop the flesh into a food processor along with 2-3 of the halved garlic bulbs, squeezed from their skins. Discard the thyme and skin.
Add the pureed pumpkin to a saucepan, finely grate the lemon zest and add juice of half the lemon, reserving the rest for later. Over a medium heat, cook the puree until most of the moisture evaporates (pumpkin has a much higher water content than potato) and it thickens, forming a dry ball, which comes away from the sides of the pan easily - this can take between 30-45 minutes so be patient, and stir regularly.
Add the flour, nutmeg and extra salt and pepper to the puree. You want it to be quite highly seasoned, as the pumpkin itself is very sweet. The dough should be soft and pliable, not overly sticky, so add more flour if necessary.
On a heavily floured surface, roll the dough into a long log, the thickness of a £2 coin, and cut into little thumb-sized pillows.
Bring a large pan of water to the boil and cook the gnocchi in batches until they float to the top. Reserve some of the pasta water for the sauce, drain and set aside on an oiled baking tray.
In a large frying pan, fry the pancetta rashers in the oil for 2-3 minutes until browned and crisp. Set aside on some kitchen paper to absorb the excess fat.
Add another tablespoon of oil to the frying pan, add the sage leaves and crisp up. Set aside with the pancetta.
Add the gnocchi to the pan and brown on all sides on a medium-high heat until they get a light golden crust. Once they have a lovely caramelisation, add the butter along with a splash of the gnocchi water and the remaining lemon juice. Vigorously toss everything together until the sauce emulsifies and thickens slightly.
Serve with broken up pieces of the pancetta, crispy sage leaves and a hefty sprinkling of parmesan.