Preheat your oven to 425°. Spray a large cookie sheet with nonstick spray. Scrub potatoes and cut them into 1-inch cubes. Place them in a large bowl.
Drizzle the olive oil over the potatoes and toss until evenly coated. Add the salt, pepper, garlic powder, and fresh rosemary; toss again.
Spread the potatoes in a single layer on the prepared baking sheet. Bake in the preheated oven at 425 degrees for 40-50 minutes, stirring a couple of times. Potatoes should be golden brown and crispy on the edges. If you cut larger chunks, they will need to cook longer.
Notes
You need the moisture in fresh rosemary for this recipe! Dried rosemary gets hard and unpalatable as it roasts.
If you use table salt instead of kosher salt, you will need to use less.