Preheat the oven to 220 °C (fan oven: 180 °C). Place the pumpkin in an ovenproof dish. Add garlic, thyme, 1 good pinch of salt and pepper and half of the olive oil and mix well.
Cover with aluminum foil and bake in the oven for 50 minutes until the pumpkin is soft. Remove the foil 10 minutes before the end of the cooking time, place the pancetta on the pumpkin and continue cooking until the pancetta is crispy.
When everything is cooked, take the baking tray out of the oven and pull the pancetta from the pumpkin. Put both aside.
Put the stock into a pot and let it simmer slightly.
Heat half of the butter and the remaining olive oil in a large frying pan, add the onion and fry at medium temperature for about 10 minutes until it is soft. Add the rice and stir until it is covered by the butter and oil.
Pour on white wine and cook until it has almost evaporated. Then add 2 ladles of the warm stock, stir and wait until the liquid is absorbed. Add 2 more ladles of stock and stir.
Repeat this process until the rice is soft and creamy. This takes about 15 minutes.
Add remaining butter, braised pumpkin, garlic and parmesan and mix. Season to taste with salt and pepper. Serve immediately with the crispy pancetta.