1. Put the lentils in a bowl, cover with cold water and leave to soak overnight. Drain well and place in a bowl. 2. Grate the onion and potato, place in a clean tea towel (dish towel) and squeeze out the excess moisture. Add to the lentils with the spices and flour and mix well. Using dry hands, roll the mixture into walnut-sized balls and place on a foil-lined tray. Cover and refrigerate for 30 minutes. 3. Heat about 2 cm of oil in a heavy-based frying pan. Add the lentil balls in small batches and fry over high heat for 5 minutes, or until golden brown. Drain on paper towels. 4. Heat another 2 tablespoons oil in a large saucepan. Add the garlic and ginger and sauté over medium heat for 1 minute, then stir in the tomato passata, stock and cream. Bring to the boil, then reduce the heat and simmer for 10 minutes. 5. Add the lentil balls, beans and carrot. Cover and simmer for 35 minutes, stirring occasionally. Serve hot, with pitta bread.