Preheat the oven to 200°C/180°C fan/gas 6.
Bring a large saucepan of salted water, acidulated with the juice of one lime, to the boil. Add the whole cauliflower and blanch for six minutes. Drain and set aside.
Place an ovenproof sauté pan large enough to hold the cauliflower over a medium heat. Add the coconut oil and allow to melt, then add the black mustard seeds and cook for about one minute, until they begin to sizzle and become fragrant. Add the ginger, garlic, chilli and turmeric and continue to cook for two minutes, stirring continuously. Add the coconut milk, season with a pinch of salt and black pepper, and bring to the boil. Add the blanched cauliflower and baste with the coconut sauce. Transfer the whole pan to the oven and bake for 30–40 minutes, basting every 10–15 minutes, until the cauliflower is tender and cooked through.
Meanwhile, make the flatbreads. In a large bowl, combine the flour, baking powder and salt, make a well in the centre and pour in the yoghurt. Bring the flour into the centre and mix together into a soft dough. Tip onto a lightly floured work surface and knead for four to five minutes until smooth. Place in a lightly oiled bowl, cover with cling film and rest for 10–15 minutes.
Portion the rested dough into walnut-sized pieces. On a lightly floured work surface, use a floured rolling pin to roll each piece of dough into a 20-cm diameter round, about 3mm thick.
Heat a dry frying pan over a medium heat. Cook each flatbread for one to two minutes on each side, until nicely puffed. Keep warm until ready to serve.
Remove the cauliflower pan from the oven, gently lift out the cauliflower and set aside. Put the pan back over a medium heat, add the black beans, the remaining lime juice and coriander and stir together until thoroughly heated through.
Portion the cauliflower into wedges and place in serving bowls. Spoon over the black bean and coconut sauce, top with toasted coconut flakes and serve with the flatbreads.