Heat oven to 200C/180C fan/gas 6. Toss the cauliflower, including the leaves, with 1 tsp cumin seeds, 1 tsp turmeric and 1 tbsp oil. Season well, spread out on a baking tray and bake for 15-20 mins or until cooked through and a little charred.
Heat 1 tbsp oil in a saucepan over a medium heat and add the remaining spices. Once the cumin seeds begin to pop, add the onion and cook for 5 mins or until softened. Stir in the garlic and ginger paste, chilli, coriander stalks and 1 tbsp olive oil, and sizzle for a few mins until fragrant. Stir in the lentils, coating them in the spices, then add the coconut milk and turn up the heat so it bubbles away. Cook for a few mins until the lentils have absorbed some of the coconut milk, then pour in the lime juice and season.
Divide the dhal into four bowls, top with the cauliflower and a scattering of coriander leaves, and serve with lime wedges on the side.