Heat the oil in a large, deep frying pan and add the onion. Stir in the garam masala, turmeric and cinnamon, and cook over a low heat for 5-10 minutes.
Add the garlic and chilli, and cook for 1 minute. Add the tomatoes and coconut milk and stir to combine. Simmer for about 10 minutes before adding the cooked lamb and the sugar snap peas. Simmer for a further 10 minutes.
Meanwhile, cook the rice and the frozen beans in separate pans to pack instructions.
Serve the curry with the rice, green beans and yogurt on the side.