Heat the oven to 400 degrees. Coat a 9-inch glass pie plate with cooking spray. Combine the olive oil and garlic in a small cup. Arrange 1 layer of potatoes overlapping in the bottom of the pan. Brush with the oil mixture. Sprinkle with the onions, salt, pepper, rosemary and cheese. Continue layering potatoes and the remaining ingredients, finishing with a final layer of potatoes, garlic mixture, salt, pepper and rosemary topped with cheese. Bake for 1 hour to 1 hour 15 minutes or until the potatoes are golden brown and tender when a fork is inserted. Cool for 10 minutes. Dollop each serving with the sour cream and a sprinkle of chives.