Chicken tikka masala

INGREDIENTS

• 4 skinless, boneless chicken breasts
• 4 tbsp readymade tandoori paste
• 2 tbsp natural yoghurt
• 3 tbsp vegetable oil or ghee ( clarified butter
• 1 cinnamon
• 8 cardamom
• 1 large onion
• 3cm/1¼in piece of fresh ginger
• 2 garlic
• 1 tsp ground cumin
• 1 tsp ground coriander
• ½ tsp turmeric
• ½-1 tsp cayenne pepper
• 1x200g can chopped tomatoes
• 150ml/5fl oz chicken stock
• 1½ tsp garam masala
• ½ lemon
• ½ tsp salt