Heat 1 tablespoon of the oil in a large pan. Add the cinnamon stick and bay leaf and cook for 30 seconds before adding the cumin seeds, ground coriander, turmeric and garam masala. Stir, then add the onion, garlic and ginger.
Turn the heat to low and cook gently for 2-3 minutes before adding the lentils and stock. Bring to the boil, then simmer for 20 minutes until the lentils are soft.
Meanwhile, cut the ends off the courgettes, slice in half lengthways then finely chop. Put in a frying pan with the remaining oil and sprinkle with a pinch of salt. Cook for 8-10 minutes until golden.
When the lentils are soft, add the coconut milk and simmer for another 5 minutes. Add the chopped fresh coriander.
To serve, ladle the dal into bowls and top with the caramelised courgette.