Heat the oil, fry the garlic until golden brown, removve with a slotted spoon and set aside. In the same oil fry the shallots until crispy, remove and set aside. Fry the chilis until they darken, remove and place in a mortar with the shallot and garlic. Pound together. Reheat the oil, add the paste and warm through. Add the sugar and salt and mix well to give a thick black/red sauce.