Spiced coconut chicken traybake

Name: Spiced coconut chicken traybake
Prep time: 10 min
Cook time: 1 h 15 min
Total time: 1 h 25 min
Cuisine: Asian, Indian
Ingredients: 8-12 whole chicken thighs; 2 tsp ground cumin; 2 tsp ground coriander; 1 tsp ground turmeric; 1 tsp mild chilli powder; 6 cardamom pods squashed; 1 tbsp grated ginger; 3 garlic cloves crushed; 1 lemon juiced; 1 tsp sea salt; 1 large onion sliced; 1 tbsp neutral oil such as groundnut or rapeseed; 1 red pepper chopped; 400g tin of coconut milk; 100g baby spinach leaves torn; basmati rice cooked to serve