Slow Cooker Pumpkin Soup

1 tablespoon olive oil
1 medium sugar pumpkin, seeded and cubed
1 medium onion, chopped
3 cups chicken stock, or as needed
1 sprig fresh rosemary
1 sprig fresh thyme
1 sprig fresh sage
2 small cinnamon sticks
2 bay leaves
1/2 cup heavy cream

Heat the olive oil in a large skillet over medium-high heat. Add
pumpkin and
onion; cook and stir until lightly browned. Transfer to a slow
cooker. Pour in
enough chicken broth to cover the pumpkin. Tie the rosemary, thyme,
cinnamon, and bay leaves into a piece of cheesecloth, and place in
the slow
cooker. Cover and cook on Low for 4 hours. After 4 hours, remove the
sachet. Stir in the cream, and puree the soup with a hand blender
until smooth.