Cut the pumpkin into quarters or eighths (depending on size) to fit into your crock pot.
Scrape out all the seeds and discard (or save to roast). Place the pumpkin pieces directly in the crockpot.
Cover and cook on low for 4 hours.
Remove the cooked pumpkin from the slow cooker and scoop out the flesh. **You'll want to let it cool first so your blender lid doesn't come popping off from the heat.
I recommend pureeing in batches to make it easier on your blender. If your pumpkin is too thick, add a little bit of water until it is just thin enough to puree. **Don't add too much water!!
Place the pumpkin puree in a seal-able container and refrigerate for up to a week. You can also put it in a freezer safe container or bag and freeze it for a few months.
Notes
The best pumpkins to use for pumpkin puree are sugar pumpkins, also commonly referred to as baking pumpkins or pie pumpkins. However, any kind of pumpkin can be used, but the texture may vary slightly.
Always cook low and slow to get the best results.
If your puree is watery, you can strain it to remove excess moisture if needed.
If your pumpkin is too thick to puree, add a little water to thin it. Be careful not to add too much otherwise it will be too watery.
You'll want to let it cool after removing it from the crock pot so your blender lid doesn't come popping off from the heat.
Use a large spoon or ice cream scoop to scoop the flesh out of the skin.