Wash and scrub potatoes and cut into bite-size pieces.
Place potatoes in a large bowl. Drizzle with olive oil. Add rosemary, salt and pepper.
Gently toss to coat.
Spread potatoes in a single layer on baking sheet, lined with parchment paper or silicone baking mat.
Roast for 15 minutes, then flip and roast for 15 more minutes.
Notes
To roast in a skillet: Simply heat up olive oil in a cast-iron skillet over medium heat. Add potatoes and saute for 4 to 5 minutes just to brown them a little bit. Place the skillet in preheated oven and roast for 15 minutes, stir and roast for 15 minutes more or until done.