Moroccan roasted vegetable soup - Good Food Middle East

Ingredients

• 1 red onion, cut into 8 wedges
• 300g carrots, cut into 2cm chunks
• 300g parsnips, cut into 2cm chunks
• 300g peeled butternut squash, cut into 2cm chunks
• 1 small potato, cut into 2cm chunks
• 2 garlic cloves
• 1 tbsp ras el hanout
• 1½ tbsp olive oil
• 1.3l hot vegetable stock
• 6 tbsp Greek-style yogurt and 1 tbsp finely chopped mint, to serve (optional)