Healthy Butter chicken curry

Name: Healthy Butter chicken curry
Prep time: 30 min
Cook time: 1 h
Total time: 1 h 30 min
Cuisine: Asian, Indian
Ingredients: Marinade; 250ml (1 cup) full cream yoghurt; 4cm piece ginger, grated (about a heaped tablespoon); 5ml (1tsp) ground turmeric; 15ml (1 tablespoon) garam masala; 10ml (2 teaspoons) ground cumin; 5ml (1 teaspoon) ground coriander; 2.5ml (1/2 teaspoon) chilli powder; generous pinch of dried red chilli paste; 15ml (1 tablespoon) lemon juice; 5ml (1 teaspoon) fine salt; 1kg (8)chicken fillets, skinless, boneless, cut into cubes; 15ml (1 tablespoon) coconut oil; 1 large brown onion, finely diced; 2 cloves garlic, minced; 30ml (2 tablespoons) tomato paste; 250ml (1 cup) tomato passata; 375ml (1 1/2 cups) weak chicken stock or water; 2 star anise; 1 thick cinnamon stick, broken in half; 15ml (1 tablespoon) salted butter (optional); fresh coriander and lemon wedges, to serve