1/2 small onion, finely chopped
1 tablespoons vegetable oil
1 tablespoons chopped fresh rosemary
¼ teaspoon salt
1/8 teaspoon ground black pepper
1 potato, washed and cut into 1-inch chunks
Preheat oven to 450 degrees F (230 degrees C). Grease a large baking sheet with a rim.
Mix onion, vegetable oil, rosemary, salt, and pepper in a large bowl; add potato pieces and toss to coat. Spread potatoes into prepared pan in a single layer.
Bake, turning occasionally, until potatoes are lightly browned and tender when pierced with a fork, 20 to 25 minutes.