Spiced Squash and Watercress Soup

Ingredients

• 1 tbsp olive oil
• 1 onion chopped
• 900g butternut squash, wash, deseeded and cut into chunks
• ½ tsp dried chilli flakes
• 600ml vegetable stock
• 1 (100g) pack watercress, roughly chopped
• 3 tbsp crème fraiche