Add prepared butternut squash, apple, pear, carrots and leek to a 6-quart or larger slow cooker crock.
Sprinkle curry powder, cinnamon and all-spice on top.
Season with salt and black pepper, to taste.
Pour chicken broth over the vegetables. Stir to combine.
Cover and cook on high for 3 hours or low for 6 hours.
When cook time is complete, remove lid and cool slightly.
Purée with an immersion blender until smooth. (If you don’t have an immersion blender, carefully transfer the vegetables in batches to a blender or food processor to process until smooth).
Pour heavy cream into a heat proof measuring cup or small bowl.
Temper the cream by adding one or two spoonfuls of the hot vegetable purée to it and stirring before adding cream to the slow cooker crock.
Blend with the immersion blender again until the cream is thoroughly incorporated into the soup and the vegetables are completely smooth. (If using a blender or food processor, temper the cream and add it while processing the vegetables).
Heat back up, necessary.
To serve, transfer soup into individual serving bowls. Top with toasted pumpkin seeds and a sprinkling of fresh chopped parsley.