Heat oven to 400F (205C). Coat rimmed baking sheet with 3 tablespoons (45ml) of olive oil; set aside.
Combine parmesan, breadcrumbs, 2 tablespoons (8g) parsley, garlic powder, ½ teaspoon (3g) salt and black pepper in a small bowl. Scatter mixture evenly on prepared sheet and nestle in baby potatoes, cut side down. Drizzle with remaining olive oil and season with remaining salt.
Roast until potatoes are tender and parmesan mixture is golden and crispy, about 30 to 35 minutes. Cool potatoes for 5 minutes. Use a knife or metal spatula to cut through cheese crust and remove potatoes to a serving dish. Scatter with remaining parsley.