Soak the lentils for 30 minutes, drain and keep aside.
In a medium-sized cast iron pot, sauté the onions with olive oil until lightly browned. Add the ginger and garlic, and sauté until fragrant.
Add the lentils and vegetable stock. Cover the pot and leave to cook on medium-low heat for about 30-45 minutes. To this, add the kale and cook until the leaves have wilted. Add the lemon juice and orange juice, and season with salt and black pepper powder.
Serve in a bowl with a squeeze of lemon for extra flavour.