Dhal with cumin-roasted cauliflower

Use up the whole cauliflower and roast the leaves too to make this moreish dhal dish. You could swap the cauli for roasted broccoli, if you prefer

200g red lentils
1 cauliflower , broken into florets, large leaves roughly chopped
2 tbsp vegetable oil
2 tsp turmeric
2 tsp black mustard seeds
2 tsp cumin seeds
1 onion , finely chopped
2 garlic cloves , grated
25g ginger , most finely chopped, some cut into matchsticks
1 tsp Kashmiri chilli
1 tsp ground coriander
1 tsp tomato purée
1 x 400g can of chopped tomatoes
small bunch of coriander , roughly chopped (save a small handful of whole leaves to serve)
4 tbsp natural yogurt , to serve (optional)

Boil the kettle, tip the lentils into a large heatproof bowl, and pour over the boiled water. Leave to soak while you roast the cauliflower.
Heat the oven to 200C/180C fan/gas 4. Spread the cauliflower and its leaves out on a large, lined baking tray. Drizzle over 1 tbsp vegetable oil, then scatter over the turmeric, mustard and cumin seeds and some salt and pepper, and massage in well. Bake for 30 mins. Once the cauliflower is golden and softened, drain the lentils.
Meanwhile, heat a large saucepan on a medium heat. Pour in the remaining 1 tbsp oil, then scatter in the onion. Cook for 10-12 mins or until softened, add the garlic and finely chopped ginger and cook for a further 2-3 mins.
Scatter in the chilli and ground coriander, and add the tomato purée, stirring well to prevent burning. Pour in the tomatoes, then 2 canfuls of water. Tip in the lentils, mixing well. Cook for 15-20 mins until the lentils are tender and the sauce has thickened. You may need to add a bit more water as it cooks, depending on the consistency you prefer.
Stir in the chopped coriander and some salt and pepper, then divide between bowls. Top with a dollop of yogurt, the cauliflower and any mustard and cumin seeds left in the tray, the ginger matchsticks and coriander leaves.