Cut a pumpkin (or other squash variety) in half and scoop out the seeds and stringy bits. Line a baking tray with aluminum foil and preheat oven to 200°C/400°F. Place the pumpkin flesh side up on the prepared tray and drizzle vegetable or avocado oil on top. Roast for 35-60 minutes, until the flesh starts to pull away from the skin and is tender enough to be easily pierced with a knife or fork. You should test in several spots to ensure it’s done. Once cool enough to handle, scoop out the flesh and place in a food processor bowl. (You may need to do this in batches depending on the size of the pumpkin and your food processor bowl.) Process until very smooth – about 3-4 minutes. Measure out what you need for this pasta dish. Then transfer the rest to a sealed airtight container. Store in the fridge for 5-7 days or freeze for up to 3 months. You can make the pumpkin puree a few days in advance if you wish.