Preheat the oven to 450°F. Spray a baking sheet liberally with cooking spray. Set aside. Clean the potatoes and remove any blemishes leaving the peel intact. Cut the potatoes into similar size chunks.
Add to a mixing bowl with the remaining ingredients, reserving 1/2 Tbsp of chopped rosemary and 2 Tbsp of grated Parmesan for garnishing.
Arrange on the baking sheet in a single layer.
Bake for 30-35 minutes until fork tender. Turn halfway through cooking for even browning. Remove from the oven, and drizzle with additional olive oil.
Toss with 2 Tbsp of grated Parmesan cheese and fresh chopped rosemary before serving.