250g/9oz carrots, peeled and roughly chopped
1 onion, roughly chopped
250g/9oz parsnips, peeled and roughly chopped
¼–½ tsp dried chilli flakes
freshly ground black pepper
1 tbsp olive oil
sea salt, to season
1.2 litres/2 pints vegetable stock
¼–½ tsp apple cider vinegar (optional)