Coriander roast chicken thighs with puy lentil salad

Name: Coriander roast chicken thighs with puy lentil salad
Ingredients: 185g puy lentils; 20g ginger peeled; 30g coriander plus extra leaves to serve; 1 tsp each garam masala and ground coriander; 1⁄2 tsp ground cumin; 2 large whole garlic cloves plus 1 small clove, finely grated; 2 tbsp lemon juice; 150g pot plain bio yogurt; 6 bone-in, skinless chicken thighs; 1 tbsp fresh turmeric finely grated; 1 tbsp rapeseed or olive oil plus 1 tsp; 3 red onions (325g), thickly sliced; 1 large red pepper and 1 large yellow pepper, deseeded and cut into chunks; 400g cauliflower cut into small florets; 1 tsp cumin seeds