Preheat your oven to 400°F.
Thoroughly wash the outside of your medium-sized white pumpkin to remove any dirt.Place the pumpkin on a sturdy cutting board. Using a sharp knife, carefully cut the pumpkin in half from top to bottom, avoiding the hard stem.
Using a large spoon, scoop out all the seeds and stringy pulp from the center of each pumpkin half. Place the pumpkin halves cut-side down in a large baking dish or roasting pan
pour water into the bottom of the baking pan. The water helps create steam as the pumpkin roasts, so it can soften Place the baking pan into the oven and roast at 400°F for approximately 1 hour, or until the pumpkin is completely soft and fork-tender. Larger pumpkins may require additional roasting time. Carefully remove the baking pan from the oven and allow the pumpkin to cool until it's safe to handle.Using a spoon, scoop the softened pumpkin flesh away from the skin. Discard the skin.
Transfer the cooked pumpkin to a blender or food processor. Blend until the pumpkin is completely smooth and creamy.