Turn your oven to 400°F / 200℃. Wash and cut the pumpkin. To cut the pumpkin hold it by the stem upright and push a large knife on the top next to the stem. Then push to the bottom. Turn the pumpkin around and do the same thing on the other side (i.e. don't try to cut through the stem). Grab the pumpkin at the bottom and pull the two sides apart. They should separate easily.
Remove the seeds. Take a spoon (maybe a large salad spoon) and just scrape the seeds and put them aside.
Place the two halves down on a baking tray.
Roast the pumpkin for about 45-60 minutes. This will depend on the size of your pumpkin and your oven. To know that the pumpkin is done, take a fork and pierce through the skin. If it goes through smoothly then your pumpkin is done.
Cool until you can grab them with your hands and scoop out the flesh with a spoon and leave the skin behind.
Place the flesh in a food processor and process until smooth – depending on your food processor could be 3-5 minutes.
Store in the fridge for 3 days and in the freezer for up to 6 months.