In a large pot, combine leeks and chicken broth. Bring to a boil, then reduce heat and simmer for 20-25 minutes, or until leeks are tender.

Carefully transfer the soup to a blender (in batches) or use an immersion blender to puree until smooth.

Return the pureed soup to the pot. Stir in the heavy cream, brown sugar, and cinnamon.

Season with salt and pepper to taste.

Serve hot, garnished with crumbled bacon.