Heat oil in a pan and sweat off the onions with the spices and garlic. Remove from pan.
Add the carrots and potatoes with 200mls of the stock, cover with a lid and bring back to the boil and simmer for 10 minutes. Remove from the pan and reserve. Add the onions and spice mix, chicken stock and lentils and bring to the boil and return to a simmer and cook for 40 minutes.
Blend the soup, bring back to the boil and add the reserved vegetables, bacon and tomato puree, then cook for 10 minutes, check seasoning and serve.