Prawn Orzo with Asparagus

• 150g Raw peeled Prawns
• 1 tbsp olive oil
• 1 onion, chopped
• 1 garlic clove, chopped
• 250g orzo pasta
• 500ml reduced-salt vegetable stock
• 125g pack asparagus tips, thinly sliced
• Salt and pepper

For the pesto

• 1 large handful herbs e.g. coriander, basil, parsley or a mix
• 1 tbsp pine nuts
• Small chunk parmesan cheese, grated
• 1-2 tbsp extra virgin olive oil
• Juice ½ lemon, plus wedges to serve
• Salt and pepper