2. Spread the vegetables and potatoes evenly on a large tray. Drizzle with olive oil and season with freshly ground black pepper. Place in the oven for 20 minutes.
3. Meanwhile, place all the ingredients for the cashew nut pesto in the food processor and whizz until smooth.
4. Remove the vegetables from the oven and make some space on the tray to add the trout fillets. Spread the cashew nut pesto evenly on top of the fish. Return the tray to the oven to cook for 12 minutes until the trout is cooked through and the vegetables are nicely roasted.