Preheat an oven to 375°F, or 400°F for crispier sweet potatoes.
Peel the sweet potatoes, and cut into 1/2" cubes. In a large mixing bowl, toss the cubes with just enough olive oil for a thin coating. Sprinkle lightly with salt and pepper.
Roast on a baking sheet for 45 minutes at 375°F, or 30 minutes at 400°F, tossing halfway through.