Curried Sweet Potato Soup

Ingredients

• 2 tablespoons olive or rapeseed oil
• 2 onions, chopped
• 4 garlic cloves, finely chopped
• 4–5cm piece of ginger, peeled and grated
• 1–2 red chillies, to taste, de-seeded and finely chopped
• 1 tablespoon garam masala
• 2 teaspoons curry powder
• 3 sweet potatoes (about 700g), peeled and cut into 2cm dice
• 1 litre vegetable stock
• 400ml tin coconut milk
• A small handful of coriander, roughly chopped
• Juice of 1–2 limes (a good tablespoonful)
• Sea salt
• freshly ground black pepper
• A few tablespoons plain (full-fat) yoghurt (optional)
• A small handful of coriander, roughly torn