Lightly spray a 20cm base saucepan with oil and heat over a medium-high heat. Add onion, garlic and ginger and cook, stirring, for 3 minutes or until softened.
Add chicken pieces and cook, stirring, for 3 - 4 minutes or un til the chicken changes colour. Add garam masala, cumin, coriander, cinnamon stick and chilli powder and cook stirring for 1 minute or until fragrant.
Add tomatoes, passata, 1 cup of water and bring to boil. Reduce heat to medium and simmer for 20 minutes or until sauce thickens slightly. Reduce heat to low. Add cream and spinach and cook stirring for 1 minutes or until spinach wilts.
Remove and discard cinnamon stick. Serve butter chicken with the cooked basmati rice.