Indian tomato and chickpea soup

Ingredients

• 2 tbsp vegetable oil
• 1 onion, peeled and grated
• 3 garlic cloves, finely grated
• 2cm knob ginger, finely grated
• 1 tsp ground fenugreek
• 1 tbsp ground coriander
• 1 tbsp ground cumin
• 1/2 tsp cayenne
• 2 tsp turmeric
• 400g canned tomatoes, chopped
• 2 tbsp tomato paste
• 400g canned chickpeas, drained and rinsed
• 1 tsp sugar
• Sea salt and black pepper
• 700ml water or stock (check stock gluten-free if necessary)
• 100g plain natural yoghurt
• 1 tomato, finely diced
• 1 tsp cumin seeds, pan-roasted
• 2 tbsp coriander sprigs