Rosemary Roasted Mashed Potatoes

Ingredients: 
8 cups baking potatoes, cut into 1-inch pieces (about 2 pounds)
1 tablespoon olive oil
1/2 teaspoon dried rosemary, crushed
1/2 teaspoon salt
1/2 teaspoon freshly ground black pepper
Cooking spray
3/4 cup hot water
1/4 cup chopped green onion
1/4 cup (1 ounce) grated fresh Parmesan cheese
1/4 teaspoon garlic powder
1 (8-ounce) container sour cream

Directions:
Preheat oven to 425°.
Combine first 5 ingredients in a shallow roasting pan coated with cooking spray; toss well to coat. Bake at 425° for 30 minutes or until tender.
Combine water and remaining ingredients in a large bowl; add potato mixture.
Mash with a potato masher to desired consistency.
Serve immediately.