Crispy Parmesan Potatoes

2 pounds medium Yukon Gold potatoes, unpeeled
4 teaspoons cornstarch
Salt and pepper
1 tablespoon extra-virgin olive oil
6 ounces Parmesan cheese, cut into 1-inch chunks
2 teaspoons minced fresh rosemary

Adjust oven rack to lower-middle position and heat oven to 500 degrees.
Spray rimmed baking sheet liberally with vegetable oil spray.
Cut thin slices from 2 opposing long sides of each potato; discard slices.
Cut potatoes lengthwise into 1/4 inch thick slices and transfer to large bowl.
Combine 2 teaspoons cornstarch, 1 teaspoon salt, and 1 teaspoon pepper in small bowl.
Sprinkle cornstarch mixture over potatoes and toss until potatoes are thoroughly coated and cornstarch is no longer visible.
Add oil and toss to coat.
Arrange potatoes in single layer on prepared sheet and bake until golden brown on top, about 20 minutes.
Process cheese, rosemary, 1/2 tsp., pepper, and remaining 2 tsp. cornstarch in food processor until cheese is finely ground, about 1 minute.
Remove potatoes from oven.
Sprinkle Parmesan mixture evenly over and between potatoes (cheese should cover surface of baking sheet),
pressing on potatoes with back of spoon to adhere.
Using two forks, flip slices over into same spot on sheet.
Bake until cheese between potatoes turns light golden brown, 5 to 7 minutes.
Transfer sheet to wire rack and let potatoes cool for 15 minutes.
Using large metal spatula, transfer potatoes, cheese side up, and accompanying cheese to platter and serve.

Serve with Chive Sour Cream

½ cup light sour cream
1 tablespoon light mayonnaise
1 teaspoon lemon juice
1 teaspoon garlic salt
1 ½ tablespoons freeze dried chives

Mix all ingredients in a bowl until combined.