Spiced root vegetable soup - Good Food Middle East

Ingredients

• 2 tbsp olive oil
• 2 onions, finely chopped
• 2 sweet potatoes, chopped
• 2 carrots, chopped
• 2 parsnips, chopped
• 1 red chilli, roughly chopped
• 1 tbsp ground cumin
• 75g dried green lentils
• 1.3l vegetable stock
• 425ml milk
• 100g Greek yogurt
• 1 tbsp coriander leaves, chopped