Heat oil in a large saucepan and add the onion, sauté a few minutes. Add the crumbed stock cubes and coat with the oil, cooking until dissolved.
Add tomatoes and mix well, cook for a few minutes then add the remaining ingredients, mixing well in the juice, cook over medium heat with lid on for about 5 minutes or so.
Add enough boiling water to just cover the vegetables. Return to the boil, reduce heat and simmer for approx. 20 mins
Mash the pumpkin and stir through the soup
Note: A can of any type of legume can be added at the end (ie. Chic peas, borlotti beans, butter beans etc.)