Heat the oil in a large pan and cook the onion for 10 minutes until just turning crisp and golden. Remove half the onion and reserve. Stir in the lamb mince and continue to cook for 5 minutes, stirring in the garlic, chilli and rogan josh paste for the last 2 minutes.
Stir in the rice and the stock and bring to the boil. Cover and cook over a low to medium heat for 10 minutes. Add in the kale for the last 4 minutes, making sure to place the lid back on top. Remove from the heat and leave to sit for 5 minutes.
Give everything a good stir and season with freshly ground black pepper. Serve with the reserved crispy onions, raita and lemon wedges.