Lightly scrub potatoes. In pot of boiling, salted water, cook potatoes until tender, about 10 minutes. Drain and let cool.
On cutting board, and using bottom of heavy saucepan, gently smash each potato until slightly flattened but not falling apart. Transfer to baking sheet. (Make ahead, Cover and refrigerate for up to 24 hours).
Drizzle with half of the olive oil, sprinkle with half each of the salt and pepper. Roast in 450F oven for 15 minutes.
Turn potatoes over; sprinkle with remaining oil, salt and pepper. Bake until golden and crispy, about 10 more minutes.