Preheat oven to 350F.

Wash pumpkin and pat dry.

Cut in half, widthwise, and scoop out seeds and stringy flesh. You can cut the stem off here as well, I was too lazy/forgot. Same result in the end.

Line a baking pan with aluminum foil, then place both halves on top, cut-side down.

Cover with aluminum foil and bake for 90 minutes. The pumpkin should be fork-tender, or you can do the poke test: poke the skin of the pumpkin and if it gives way easily, it should be done.

Remove from oven and let cool.

Scoop the cooled flesh into a food processor, discarding the stem and outer skin.

Purée until you have blitzed through all the chunks.

Now if you want, strain the pumpkin purée through a mesh sieve or better a cheesecloth. You'll probably get 1 cup of liquid, and this gives you a more concentrated pumpkin purée that has a similar consistency to canned pumpkin purée.

Store in a jar or air-tight container for up to 1 week. Use just like you would use canned pumpkin =)