Heat a large saucepan over medium heat. Add sausage, tomato paste, allspice, garlic powder, fennel seed, red pepper flakes and salt. Stir to combine and cook for 5 minutes.
Add onions to the saucepan and cook for an additional 5 minutes, or until onions are softened.
Add pumpkin, kale, broth and water to the pot. Bring to a boil and reduce the heat to low. Simmer, uncovered, for approx. 20 minutes.
Add vinegar and stir. Taste and season with salt and red pepper flakes as desired.
Serve with grated parmesan cheese and sprinkling of chives (if using) on top.