Indian lentil soup

Ingredients

• 1 tablespoon vegetable oil
• 1 onion, finely chopped
• 1 teaspoon cumin
• 1 teaspoon turmeric
• 1 teaspoon ground coriander
• 1 clove of garlic, peeled and diced
• ½–1 red chilli, deseeded and finely chopped
• Small piece fresh root ginger, peeled and finely chopped
• 3 tomatoes, roughly chopped
• 250g split red lentils, rinsed
• 900ml boiling water
• Small handful fresh coriander, roughly chopped
• Freshly ground black pepper