Preheat oven to 450 degrees F. Lightly oil a rimmed baking sheet and set aside.
Set potatoes in a large pot of cold water and bring to a boil. Salt the water. Boil potatoes until fork tender, 8 - 10 minutes. Drain and set potatoes on a rimmed baking sheet.
Cut a small x on the top of each potato and then use a glass or something with a flat bottom to smash it. There’s a bit of an art to neither over- nor under-smashing — it’s fine if a few fall apart. Brush smashed potatoes with olive oil, and sprinkle with sea salt and black pepper. Slide into the oven and bake for 20 – 25 minutes, or until potato edges are golden brown.