Combine all ingredients except for vanilla extract into a slow cooker and stir well.
Slow cook for 8 hours on low setting, stirring occasionally. If you use fresh pureed pumpkins, note that it may be more watery than the canned stuff, so you may need to cook a bit longer. Look for a thick consistency, thicker than applesauce, but not quite to a jam thickness.
Let cool, then stir in vanilla extract.
Add to jars. Refrigerate or freeze (if freezing in glass, leave at least 1 inch (2.5 cm) head space to allow for expansion.
Lasts in refrigerator up to 2 weeks.