Place beans and tomatoes in a food processor; cover and process until blended. Set aside., In a Dutch oven, saute onions in oil until tender. Add garlic and cumin; saute 1 minute longer. Stir in the broth, pumpkin, vinegar, pepper and bean mixture. Bring to a boil. Reduce heat; cover and simmer for 20 minutes., Stir in bourbon if desired. Garnish each serving with sour cream, green onions and pumpkin seeds.