Murgh makhani (Butter chicken)

Name: Murgh makhani (Butter chicken)
Prep time: 40 min
Cook time: 1 h 15 min
Total time: 1 h 55 min
Cuisine: Asian, Indian
Ingredients: 800 g chicken thigh fillets, each thigh cut into 8 pieces; 30 g lemon juice; ¼ tsp salt; 150 g natural yoghurt; 120 g tandoori paste (see Tips); oil, for greasing; 2 tsp cumin seeds; 2 tsp coriander seeds; 2 cm cinnamon quill; 1 black cardamom pod; 1 tsp fenugreek seeds; 45 g ghee (see Tips); 1 - 2 brown onions (approx. 180 g), cut into halves; 20 g ginger paste (see Tips); 10 g garlic paste (see Tips); 1 tsp salt; 2 fresh long green chillies, trimmed and cut into halves (optional); 20 sprigs fresh coriander, leaves, stalks and roots, cut into thirds, plus extra leaves for garnishing (see Tips); 400 g canned whole tomatoes; 70 g water; 70 g cashews, plus extra for garnishing; 40 g unsalted butter; 1 tsp garam masala (see Tips); 100 g pouring (whipping) cream