Gently heat the oil in a medium sized pan then add the cinnamon stick, onion and ginger and garlic paste. Sauté for 4 -5 minutes until the onion is softened.
Stir in the rinsed yellow split peas, chilli powder, chopped chillies and turmeric. Cook everything together, stirring for 2 - 3 minutes. Then add the drained tomatoes and cook again, stirring for another 2 - 3 minutes.
Remove cinnamon stick, pour in the water, and bring to the boil then turn down to simmer for about 40 minutes until the split peas have softened and broken down.
Press the split peas against the edge of the pan with the back of a spoon to speed up the cooking or mash them if you like.
Season to taste, stir in the coriander and serve with Indian breads or basmati rice.