Preheat the oven to 400 degrees Fahrenheit. Cut one of the pumpkins vertically in half and scoop out and discard the seedy pulp. Place the pumpkin on a baking sheet and rub the inside with a teaspoon of the olive oil. Roast until tender when pierced with a fork, about 45 to 55 minutes. Remove from the oven and use a spoon to scoop out the tender flesh and place it in a heat-safe bowl. Set it aside.
Now take the other pumpkin and cut off the top as you would with a carving pumpkin. Use a medium sized spoon to scoop out all of the seeds pulp and discard it.
Sprinkle some salt inside the pumpkin and spread a tablespoon of olive oil inside of it and place the cap back on. Place this pumpkin in a casserole pan and roast in the oven for 45-60 minutes, or until the inside of the pumpkin is fairly soft and the outside has turned a deep orange color. Remove and set aside.
While the second pumpkin is roasting, heat the remaining olive oil in a very large pot over medium heat. Add the onions and sauté until nearly transparent, about 10 minutes. Then add the potatoes, carrots and coriander. Cover, reduce heat to medium low, and allow to cook for 20 minutes, stirring every five minutes to cook the vegetables evenly.
Then add the garlic, ginger, leek, tomato, and the scooped roasted pumpkin bits and allow to cook for 20 minutes, stirring every five minutes again. Add the water, boullion cubes, paprika, cloves and cayenne pepper and mix well. Cover and let simmer for 30 minutes, stirring every 10 minutes.
Taste it and add salt if you'd like, then ladle it into a blender or food processor and make a puree of the soup. Ladle the pureed soup into the roasted pumpkin and serve it hot with a side of chopped cooked bacon (optional) and an herb sprig for garnish.