Potatoes and Onions - Baked

Courtesy of Giada De Laurentiis.
Yields about 4 to 6 servings.

2 lbs. new potatoes (white, red or Yukon gold), washed and halved
1 onion, coarsely sliced
1/4 cup extra-virgin olive oil
2 tsp. dried rosemary
1 tsp. salt
1 tsp. pepper

Heat oven to 400.
In a large bowl, toss together all the ingredients.
Spread the mixture in a single layer on a baking sheet.
Bake until the potatoes are tender, about 40 minutes.
Serve.