Place a large soup pot on the stove over medium high heat; add the oil. Then add the onion and sauté for about three minutes. Be careful not to let it get too brown because a burnt flavor will permeate the soup. Add the curry powder, cumin, cardamom, turmeric, granulated garlic and garlic salt to the pot. Cook for an additional minute, constantly stirring. This helps release the essential oils in the spices.
Pour in the coconut milk, pumpkin, crushed tomatoes and chicken broth. Bring to a gentle simmer and cook for about 10 more minutes.
To serve, ladle into bowls and top with chives and yogurt, if desired.