Place a large sheet pan in a cold oven, then preheat the oven to 500°F.
In a large pot, bring 8 cups water to boil. Add potatoes, salt, and baking soda. Return the pot to a boil, then reduce heat to simmer. Cook the potatoes for 5 minutes.
Drain the potatoes in a colander and shake vigorously to roughen edges. Transfer potatoes to a large bowl and toss with 1 tablespoon olive oil and pepper. Working quickly, carefully remove the sheet pan from the oven and pour the remaining 1 tablespoon oil onto the surface. Arrange the potatoes on the sheet in an even layer.
Bake until potatoes are crisp and skins are deep golden brown, about 20 to 25 minutes, stirring halfway through roasting.