Preheat oven to 425 F. Line a baking sheet with aluminum foil and lightly brush with olive oil. Set aside.

Bring a large pot of salted water to a boil. While the water is heating, wash the potatoes. When the water comes to a  boil, add the potatoes and cook for 15-20 minutes or until easily pierced with a fork (time will vary depending on the size of the potatoes and elevation.)

When the potatoes are fork tender, use a slotted spoon to transfer them to the prepared baking sheet. Use a flat-bottomed glass or bowl to smash the potatoes, then brush generously with pesto. Season with salt and pepper. Transfer to oven and bake for 10 minutes or until the edges are crispy. Top with shredded cheese and return to oven for 1-2 minutes or until cheese is melty. Serve immediately.