- Place rimmed baking sheet on upper-middle oven rack. - Preheat oven to 450. - Meanwhile, toss potatoes, cornstarch, garlic powder, 3/4 teaspoon salt, and 1/2 teaspoon pepper together in large bowl. - Carefully remove preheated baking sheet form oven. - Add oil and tilt baking sheet to evenl y coat with oil. - Place potatoes, cut side down in single layer on baking sheet. - Roast until browned around edges, about 30 minutes. - While potaotes roast mix butter, garlic, parsley, and lemon zest together in a large bowl. - Remove baking sheet from oven and flip each wedge over. - Roast until potatoes are crispt and deep golden brown, 10 -15 minutes. - Transfer potatoes to bowl with butter and toss until evenly coated. - Season with salt and pepper. - Serve immediately.