Preheat your oven to 425°F (220°C). This high temperature is key for achieving crispy potatoes.
Wash the small white or red potatoes thoroughly. Halve or quarter them depending on their size. Aim for uniform pieces to ensure even cooking.
In a large mixing bowl, combine the halved or quartered potatoes with the pesto, grated parmesan cheese, salt, and pepper. Toss well until the potatoes are evenly coated with the pesto mixture.
Spread the seasoned potatoes in a single layer on a rimmed baking sheet. Make sure they have enough space to roast rather than steam, which is crucial for getting that perfect crispy texture.
Place the baking sheet in the preheated oven and roast for about 25-30 minutes. Halfway through, use a spatula to flip the potatoes to ensure they are golden and crispy on all sides.
Once the potatoes are fork-tender and beautifully golden brown, remove them from the oven. Allow them to cool slightly before serving. Enjoy as a side dish or a tasty snack!