Preheat oven to 400° F. Spray a rimmed baking sheet with cooking spray, you can also line it with foil.

In a bowl toss the potatoes, pesto, salt and pepper together until coated. Spread them into an even layer on the prepared baking sheet. Roast in the oven for 20 minutes then remove the pan and sprinkle the potatoes with the parmesan cheese. Bake another 5-10 minutes or until the outside of the potatoes are crisp and the inside is fork tender.

Once the potatoes are roasted squeeze the juice of half of a lemon over the top of them. Serve the potatoes on a serving plate or bowl drizzled with extra pesto and more parmesan cheese.