Lemon pepper tarka dal

Name: Lemon pepper tarka dal
Ingredients: 200g/7oz red lentils; 2 tbsp ghee; 1 medium onion, grated; 1 tbsp grated ginger; 2 garlic cloves, crushed; 1 large tomato, chopped; ½ tsp ground turmeric; ½ tsp chilli powder; ½ tsp ground coriander; ½ tsp garam masala; 1½ tsp salt; 1 litre/1¾ pint boiling water; pinch bicarbonate of soda; 2 tsp lemon juice; 1 tbsp chopped fresh coriander, to garnish; 1 tsp cumin seeds; ½ tsp ground black pepper; 8–10 fresh curry leaves; 1 tbsp chopped coriander stalks; 1 large lemon, zest only