Pea and Parsley Soup - River Cottage

Ingredients

• 1 tablespoon olive or rapeseed oil, plus extra to trickle
• 20g butter
• 1 medium onion, finely chopped
• A few sprigs of thyme, leaves only, chopped
• 1 litre vegetable stock
• 500g fresh shelled peas, or frozen peas
• 20g flat-leaf parsley, chopped
• Sea salt and freshly ground pepper, to taste
• A few mint leaves, shredded, to finish (optional)