In a large saucepan put the pumpkin - peeled and cut into pieces, chopped tomatoes and onions, the butter, coriander, nods, nutmeg salt and pepper to taste. Cover and stew about 20 minutes, occasionally shaking the pan. Pour the chicken broth into the pan and boil after boil 15 minutes or until pumpkin is tender. Removing the pan from the heat and set aside to cool. Blend to a smooth homogenous mixture. Transfer the soup into a clean saucepan, warm again, seasoned, if necessary. Serve flooded with cream and sprinkled with coriander.