Indian spiced tomato soup

• 1 onion , roughly chopped
• 2 tsp garam masala
• pinch chilli flakes
• 2 tbsp red lentils
• 1 x 400g tin chopped tomatoes
• 500ml vegetable stock
• ½ bunch coriander , chopped
• natural yogurt , to serve (optional)

1. Put all the ingredients (exceptthe coriander and yogurt) in a pan, bring to a simmer and cook for 20 minutes until the lentils are soft. Add the coriander and cook for a minute. Use a stick blender to roughly whizz together.
2. Stir in a little natural yogurt to serve if you like.