Heat up olive oil in sauce pan. Fry off onions until they start to turn brown. Add bacon lardons and fry off with onions until they are nearly cooked.
Add the chilli, red lentils, tomatoes, water, cumin and basil, and keep stirring. Once the soup starts to boil, turn the heat down to low and leave to simmer for 20-25 minutes. Add more water to the soup if you feel its too thick, but this may reduce the taste later.
Once the soup is to your satisfaction, season it and stir it in. Then use a hand blender or food mixer to smooth the soup to your desired consistency (whether you require a thick hearty soup, or a thin smooth soup).
Serve the soup with a crusty roll and a dollop of soured cream on the soup.