In a blender, puree the green tomatoes, jalapeno chillies, lettuce and coriander until smooth. Set aside.
In a frypan fry the onion and garlic until just browned. Under the grill, toast the tortilla and the bread roll. In a small frypan, toast the sesame seeds, cinnamon stick, pepper and clove. Place all in a food processor and grind.
Heat the oil in a saucepan over medium heat. Add the tomato puree, the onion paste and the ground spices. Simmer on low heat, stirring constantly. Add chicken stock gradually until you reach the desired consistency.