In a large pot, on a medium heat, sauté the onions, garlic, carrots, celery and leeks with the oil, until translucent. This will take 7-8 minutes, stir occasionally.
Add the sugar and sauté for a minute to caramelize the veggies.
Continue with the veggie cube, tomato paste and dried herbs. Sauté for a minute before you add the butter beans, bay leaf and plum tomatoes.
Break the tomatoes with a wooden spoon and add 400ml of boiling water.
Bring to boil and simmer covered for 30 minutes, stirring occasionally.
Check the seasoning and add the fresh herbs.
Serve with kalamata olives, onions and bread of choice (I used garlic bread). You can keep it in the fridge for up to 5 days and you can also freeze it.